Silence Therapeutics plc
The Royal Institution of Great Britain 
21 Albemarle Street 
London W1S 4BS
Tel:  +44 (0) 20 7491 6520 
Fax:  +44 (0) 20 7491 6521 
email:  mail@silence-therapeutics.com
website: www.silence-therapeutics.com
Silence Therapeutics plc Annual report and accounts 2009
 Silence Therapeutics plc
Annual report  
and accounts 2009 Registered office
22 Melton Street 
London NW1 2BW
Registered number 
2992058
Nominated advisers
Nomura Code Securities Ltd
1 Carey Lane 
London EC2V 8AE
Registrars
Capita IRG plc
Northern House 
Woodsome Park 
Fenay Bridge 
Huddersfield HD8 0LA
Auditor
Grant Thornton UK LLP
Grant Thornton House 
Melton Street 
Euston Square 
London NW1 2EP
Silence Therapeutics plc 
is a leader in the 
of 
novel RNA interference (RNAi) 
therapeutics for the 
RNA interference, a Nobel Prize winning 
technology, is one of the most exciting areas 
of drug discovery today as it can selectively 
“silence” genes linked to the onset of disease, 
thus leading to the creation of a new class of 
therapeutic products, RNAi therapeutics.
We aim to establish Silence Therapeutics 
as a partner-of-choice for the world’s leading 
pharmaceutical companies.
Review of the year
 01  Highlights of 2009
 02  Post year-end highlights
 04 Chairman’s statement
 06 Chief Executive’s review
Corporate governance
 10 Board of directors
 12 Directors’ report
Financial statements
 16 Independent auditors’ report
 17 Consolidated income statement
   Consolidated statement 
of comprehensive income
 18 Consolidated balance sheet
 19   Consolidated statement 
of changes in equity
 20 Company balance sheet
 21   Company statement 
of changes in equity
 22 Cash flow statements
 23 Notes to the financial statements
 43 Company information and advisers
 44 Notice of Annual General Meeting
 45  Explanatory notes to the notice 
of Annual General Meeting
 47 Form of proxy 01
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
Highlights of 2009
Operational
  Silence initiated a Phase I clinical trial of Atu027, its lead drug candidate for the 
treatment of advanced solid tumours. The trial, being conducted at the Marienhospital, 
Herne, Germany, is an open‑label, dose‑finding study to address the safety, tolerability 
and pharmacokinetics of Atu027. It is expected that results from the trial will be available 
in the second half of 2011. 
  Silence’s licensing partner, Quark Pharmaceuticals, commenced Phase I/II clinical 
trials with QPI‑1002, a short interfering RNA (siRNA) therapeutic product candidate in 
development for use in kidney transplants. QPI‑1002 is based on Silence’s proprietary 
AtuRNAi chemistry.
  The European Patent Office (EPO) granted a patent on protein kinase N3 (PKN3), 
the target gene for Silence’s lead compound Atu027.
  The Technical Board of Appeal of the European Patent Office revoked in its entirety 
European patent EP1 214 945, which is a fundamental competitor patent owned by 
Alnylam Europe AG.
  Silence entered into a delivery collaboration with Dainippon Sumitomo Pharma Co., Ltd 
of Japan to demonstrate the functional delivery of Silence’s proprietary siRNA molecules 
to specific targets. The collaboration is evaluating Silence’s proprietary AtuRNAi, a novel 
proprietary siRNA molecule which is chemically modified to improve stability, reduce 
manufacturing costs and increase yield. The collaboration is also making use of Silence’s 
AtuPLEX delivery technology, which has been shown to improve functional intracellular uptake. 
  The Opposition Division of the EPO upheld Silence’s core AtuRNAi patent EP 1 527 176 
(’176) in amended form. The amended form of patent ’176 covers Silence’s proprietary 
blunt‑ended siRNA molecules containing alternating 2’‑O‑Methyl modifications.
Financial
  Revenue generated in the year was £1.72m (2008: £2.21m).
  Administrative expenses increased to £4.20m (2008: £3.29m).
  Research and development expenditure decreased to £5.07m (2008: £6.71m).
  The cash position at year‑end was £1.13m. A further £15.0m (gross) was raised shortly 
after the year end through an institutional placing that closed in January 2010. At the end 
of 2008, Silence had cash of £3.35m. 02
Silence Therapeutics plc Annual report and accounts 2009
Post year-end highlights
By combining the expertise 
of both Intradigm and Silence, 
we now have 
delivery technology platforms.
PF-4523655 Diabetic macular oedema Pfizer/Quark     Local delivery to the eye 
(AtuRNAi)
PF-4523655 Age‑related macular degen Pfizer/Quark    Local delivery to the eye 
(AtuRNAi)
QPI‑1002 Acute kidney injury Quark    Systemic delivery to the kidney 
(AtuRNAi)
QPI‑1002 Prevention of delayed graft function Quark    Systemic delivery to the kidney 
(AtuRNAi)
Atu027 GI & lung and other cancers  Internal    Systemic delivery to tumour 
(AtuRNAi)      endothelium
Atu134 Acute lung injury  Internal    Systemic delivery to lung 
(AtuRNAi)      endothelium
Atu111 Solid tumours  Internal    Systemic delivery to tumour  
(AtuRNAi)      endothelium
Atu150 Solid tumours Internal    Systemic delivery to tumour 
(AtuRNAi)      endothelium
At least half of the siRNA therapeutics currently in clinical trials are based on Silence technology.
Product Indications Partners Preclinical Phase I Phase II Status
Our product pipeline
Naked siRNA
Naked siRNA
Naked siRNA
Naked siRNA
DACC8
AtuPlex
AtuPlex
AtuPlex 03
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
Post year-end operations
  Silence merged with US-based RNAi therapeutic company Intradigm Corporation 
(Intradigm) on 5 January 2010 to form a leading company in the field of RNA 
interference. The merger was effected by the issue of Silence shares to the shareholders of 
Intradigm such that the Intradigm shareholders at the time of the merger owned approximately 
36% of the issued share capital of Silence. The merger offers a number of strategic benefits 
including multiple RNAi discovery, development and delivery technologies, a broad internal 
and partnered product pipeline and a strong portfolio of intellectual property. 
  In parallel with the merger, Silence Therapeutics raised £15m (gross) through an 
institutional placing and a subscription of shares at a price of 23p per share. The funds 
raised will support the Company’s ongoing development efforts and provide the strength 
from which to pursue additional partnerships and development deals.
  Upon completion of the merger, Philip Haworth, J.D. PhD, former chief executive officer of 
Intradigm, assumed the role of Chief Executive Officer of the enlarged Group.
  The United States Patent and Trademark Office (USPTO) issued the Company a notice 
of allowance on a patent application directed to methods of treatment using PKN-3, 
a high-value therapeutic target in the area of oncology. 
  Silence and Dainippon Sumitomo Pharma Co., Ltd agreed to expand their ongoing 
siRNA delivery collaboration to examine delivery of RNAi therapeutics to additional disease 
targets selected by Dainippon Sumitomo. 
  Silence announced a strategic plan designed to optimally organise its resources 
following its recent merger with Intradigm. Moving forward, all research activities related to 
Silence’s novel RNAi therapeutic platforms, including technologies that have emerged from 
both Silence and Intradigm, will take place at the Company’s Berlin location. Other functions 
including operations, business development, legal and certain drug development activities 
will be conducted in Palo Alto. Silence expects this move to result in a significant reduction 
in the Company’s operating costs moving forward. 
  Silence and AstraZeneca agreed to an extension of their ongoing siRNA delivery 
collaboration to examine new and enhanced delivery approaches for RNAi therapeutics. 
Post year-end Board and management changes
  Silence announced a Board change with the resignation of Iain Ross as Chairman.  
Jerry Randall, who was appointed to the Silence Board in 2008, was appointed 
Non‑executive Chairman.
  Silence announced a management and Board change with the resignation of Melvyn Davies 
as Chief Financial Officer. Silence also announced the appointment of Max Herrmann as the 
Company’s Chief Financial Officer and Company Secretary with effect from 4 May 2010. Silence Therapeutics plc Annual report and accounts 2009
04
Chairman’s statement
2009 was a defining year for Silence Therapeutics. 
Each of the Company’s internal programmes 
advanced steadily – we entered into a new 
collaboration with Dainippon Sumitomo and 
made excellent progress with each of our 
pharma partnerships, and we strengthened 
our intellectual property position by expanding 
our portfolio of filed and issued patents.
Despite our many internal successes, the 
turbulence of the world’s financial markets created 
a significant degree of uncertainty that required 
the Company’s attention and decisive action. 
In an effort to address the declining opportunity 
for financing and the erosion of our share value, 
we began to evaluate our options, with the goal 
of achieving the following objectives:
  establish Silence as a partner‑of‑choice 
for the world’s leading pharmaceutical 
companies; 
  expand our technology base to allow us 
to best address the challenges of RNAi 
delivery; and
  secure additional financing for 
the Company.
The merger with Intradigm Corporation, which 
was completed in January 2010, took Silence 
Therapeutics a long way to achieving these goals 
including a concurrent financing of £15.0m (gross). 
As a result, Silence is now better funded and holds 
a strong strategic position in the three areas 
we believe are critical to building, protecting 
and commercialising RNAi therapeutics: 
  Proprietary delivery technologies 
  Silence’s delivery platform is one of the 
industry’s broadest, including both lipid 
and polymer technologies, offering drug 
developers an increased opportunity for 
successful delivery to specific tissues 
to cause specific therapeutic benefits. 
  Potent siRNA sequences 
  Silence has issued and pending patents 
on multiple high‑value siRNA sequences 
of varying structure. 
  Innovative siRNA structural features 
  Silence has issued and pending patents directed 
to one of the industry’s most advanced siRNA 
chemical modification technologies optimised 
for improved stability, yield and safety.
  Silence’s exclusive licences from the University 
of Massachusetts provide access to issued and 
pending patents associated with the Zamore 
“Design Rules” including methods for increased 
potency and reduced off‑target effects. 
A key factor in establishing Silence as a 
partner‑of‑choice for pharmaceutical companies 
is our ability to provide novel and effective siRNA 
delivery solutions. As it is not likely that the vast 
range of siRNA delivery challenges will be addressed 
by a single platform, we believe it’s critical to build 
a broad toolbox of solutions and technologies. 
By combining the impressive expertise of both 
Silence and Intradigm, we now have one of the 
industry’s most comprehensive and versatile 
delivery technology platforms, providing Silence 
with unmatched potential to develop solutions 
for successful siRNA delivery to particular tissues 
to cause specific therapeutic benefits. The combined 
assets of the new Company have drawn the attention 
of a number of leading pharmaceutical companies 
worldwide and we are actively engaged in partnering 
discussions spanning a range of new and 
exciting development opportunities. 
In summary, the merger combined the strength 
of two innovative entities and created a new 
leadership in RNAi therapeutic development. 
“ A key factor in 
establishing Silence 
as a partner-of-choice 
for pharmaceutical 
companies is our 
ability to provide 
novel and effective 
siRNA delivery 
solutions.”  05
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
As a result, we have succeeded in establishing 
a new company with the following strengths 
and advantages: 
  Comprehensive platform of technologies 
capable of addressing the discovery, 
development and delivery of RNAi 
therapeutics. Capabilities extend to all essential 
areas for successful product development 
including formulation and drug delivery, 
siRNA structure and chemistry and a diverse 
library of therapeutic siRNA sequences. 
  Advancing pipeline of internal and partnered 
product candidates. At least half of the siRNA 
programmes currently in clinical development 
globally incorporate Silence’s technology. 
These include product candidates that are 
being advanced by partners such as Pfizer 
and Quark Pharma.
  Broad and diverse intellectual property 
portfolio. IP protection covering essential 
areas of RNAi therapeutic development 
(target sequences, delivery and siRNA 
structural features).
  Validating partnerships with global 
pharmaceutical companies. The multiple 
major partnerships with companies such 
as AstraZeneca, Pfizer, Quark Pharma 
and Dainippon Sumitomo demonstrate 
the credibility of Silence’s technologies. 
  Experienced management team and 
Board of Directors. Our new management 
team, Board and recent reorganisation 
provide the expertise and focused skills 
required to advance Silence’s discovery 
and development activities.
  Expanded financial support and stability 
to facilitate new growth opportunities. 
International shareholder base offers broader 
access to capital, which should ultimately 
provide additional strength to negotiate 
favourable strategic transactions. 
We believe the merger produced a stronger, 
more stable and technologically sophisticated 
Company that is well positioned as a new leader 
in RNAi therapeutic development. We are actively 
developing our strategic plan for the near term, 
and we will continue to take all steps required 
to advance our internal and partnership programmes, 
as well as establish new collaborations to fuel 
our pipeline in the future.
We are grateful for the support of our shareholders 
and new investors alike and we wish to assure 
them both that we are committed to building 
corporate value through meaningful scientific 
progress and additional high‑value partnerships 
with the pharmaceutical industry. 
Thank you for your continued support 
of Silence Therapeutics. 
Jerry Randall ACA
Chairman 
The merger 
 of two innovative 
companies and created a 
 in RNAi 
therapeutic development. 06
Silence Therapeutics plc Annual report and accounts 2009
Chief Executive’s review
Overview
In 2009, a number of pivotal events provided 
the foundation and framework that will propel 
Silence forward in 2010 and beyond. During 
the year, the Company made progress on all 
fronts – in the clinic, with partnerships, financially 
and in securing critical intellectual property (IP). 
These successes opened the door for further 
opportunity, culminating in the merger with 
Intradigm on 5 January 2010. We believe 
post‑merger Silence is a new leader in RNAi 
therapeutic development with a unique potential 
to develop delivery solutions that can be tailored 
to address various therapeutic requirements. 
With our expanded technologies and assets, 
we are aggressively executing a plan designed 
to further strengthen the business and create 
increasing value for our shareholders. 
Before looking ahead, I’d like to address each 
of the critical 2009 events that contributed to 
our new Company and our future opportunities. 
Operational
Progress in the clinic
In 2009, we made great strides in the clinic with two 
of our programmes in human trials. In January 2009, 
our licensing partner, Quark Pharmaceuticals, 
commenced a Phase I/II clinical trial with QPI‑1002, 
its RNAi drug targeting the p53 gene for the 
prevention of delayed graft function (DGF) following 
kidney transplants. QPI‑1002 incorporates Silence’s 
AtuRNAi technology and we believe this independent 
advancement of our technology represents 
a significant validation of Silence’s science and drug 
candidates. While this programme is managed 
by Quark, we believe the trial is progressing 
as planned and we look forward to the results.
In June 2009, Silence initiated a Phase I study 
of Atu027, our lead drug candidate for the treatment 
of advanced solid tumours. The trial, being 
conducted at the clinical study centre of the 
Cancer Hospital SanaFontis in Freiburg, Germany, 
is an open‑label, dose‑finding study to address 
the safety, tolerability and pharmacokinetics 
of Atu027. This trial has eleven dosing regimens. 
We are advancing through the dosing protocol 
as planned and we remain on target to have results 
in the second half of 2011. 
Atu027 specifically targets PKN3, a molecule 
involved in cancer growth and metastasis formation. 
Atu027 is Silence’s most advanced clinical 
candidate for a systemically delivered siRNA 
using the Company’s proprietary AtuPLEX 
delivery technology. It is our belief that Atu027 
may ultimately be a valuable treatment option 
for cancer patients that do not respond to 
standard therapy.
We are executing a plan designed 
to the business 
and create for 
our shareholders. 07
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
Silence is also working to develop three pre‑clinical 
programmes. Atu134 is being evaluated for potential 
treatment of acute lung injury and Atu111 and 
Atu150 are both being evaluated for the potential 
treatment of solid tumours.
Expanding our collaborations
In August 2009, Silence expanded its partnerships 
with the addition of a new collaboration with 
Dainippon Sumitomo Pharma Co., Ltd of Japan. 
The purpose of the collaboration is to demonstrate 
the functional delivery of Silence’s proprietary 
siRNA molecules to specific targets. The ongoing 
collaboration is currently evaluating Silence’s 
proprietary AtuRNAi molecule that is chemically 
modified to improve safety, reduce manufacturing 
costs and increase stability. The collaboration 
is also making use of Silence’s AtuPLEX delivery 
technology, which has been shown to improve 
functional intracellular uptake.
Though this collaboration is currently only 
seven months old, we were pleased to announce 
in March 2010 that Dainippon Sumitomo has 
elected to expand this collaboration by examining 
delivery to additional disease targets that were not 
originally specified under the initial collaboration. 
As a company focused on addressing the challenges 
of RNAi delivery, we are very pleased that Dainippon 
Sumitomo has elected to expand our collaboration 
so quickly. We believe this is a strong testimony 
to the potential of our delivery technology as well 
as the value we bring our partners. 
In addition to our partnership with Dainippon 
Sumitomo, we currently have two ongoing 
collaborations with AstraZeneca, which were initiated 
in June 2007 and March 2008. The June 2007 
collaboration was established for the purpose 
of developing novel siRNA therapeutics against 
specific targets exclusive to AstraZeneca, and 
the March 2008 collaboration seeks to develop 
a range of novel approaches for the delivery of 
siRNA molecules. These collaborations continue 
to advance as planned and we, together with 
our partners, are very pleased with the progress 
to date. We look forward to providing updates 
on these collaborations in the near future.
Building financial strength
In January 2009, Silence raised £2.65m net 
of expenses through the issue of 15m shares 
at a price of 18p per share. Concurrent with 
our merger with Intradigm in January 2010, 
we raised an additional £15m (gross) at a price 
of 23p per share. Such funds are intended 
to support the Company’s ongoing development 
efforts and provide a position of strength as 
we work to pursue additional partnerships 
and development deals.
Beyond the funding itself, it is important to note 
who invested in each of these rounds. We are 
fortunate to have the support of several pre‑eminent 
institutions in the UK, as well as several leading 
US institutions. We are also very fortunate to have 
the financial backing of a number of strategic 
pharmaceutical venture groups including Lilly 
Ventures, Roche Finance and Astellas Venture, 
who were investors in Intradigm.
Enhancing our intellectual property estate
The importance of intellectual property to success 
in the RNAi therapeutic field cannot be overstated. 
Yet, we argue that the true value of IP lies in 
the specific claims as opposed to the number 
of patents. During 2009 and continuing in 2010, 
both Silence and the former Intradigm secured 
a number of pivotal patents that are all now 
owned by post‑merger Silence. The following 
events contributed significantly to the strength 
of Silence’s IP estate:
  the European Patent Office (EPO) granted 
a patent on protein kinase N3 (PKN3), the target 
gene for Silence’s lead compound Atu027;
  the Technical Board of Appeal of the European 
Patent Office revoked in its entirety European 
patent EP1 214 945, which is a fundamental 
competitor patent owned by Alnylam Europe AG; 
  the Opposition Division of the EPO upheld 
Silence’s core AtuRNAi patent EP 1 527 176 
(’176) in amended form. The amended form 
of patent ’176 covers Silence’s proprietary 
blunt‑ended siRNA molecules containing 
alternating 2’‑O‑Methyl modifications; and
“ In August 2009, 
Silence expanded 
its partnerships with 
the addition of a new 
collaboration with 
Dainippon Sumitomo 
Pharma Co., Ltd 
of Japan.” Silence Therapeutics plc Annual report and accounts 2009
08
Chief Executive’s review continued
Operational continued
Enhancing our intellectual property estate 
continued
  the United States Patent and Trademark 
Office (USPTO) issued a notice of allowance 
on a patent application directed to methods 
of treatment using PKN‑3, a high‑value 
therapeutic target in the area of oncology. 
The allowed subject matter is directed to, 
among other things, methods of treating 
cancer with siRNA or antisense molecules 
that target the PKN‑3 messenger RNA (mRNA). 
The claims cover the siRNA molecule in 
Silence’s lead clinical compound, Atu027, 
an RNAi therapeutic that targets PKN‑3 for 
the treatment of advanced solid tumours.
In addition to these events, Silence also now 
owns key intellectual property rights previously 
secured by Intradigm as follows:
  issued and pending patents on multiple 
high‑value siRNA sequences of varying 
structure;
  issued and pending patents directed to 
one of the industry’s most advanced siRNA 
chemical modification technologies optimised 
for improved stability, yield and safety; and
  three exclusive licences from the University 
of Massachusetts to the issued and pending 
patents associated with the Zamore “Design 
Rules” including methods for increased 
potency and reduced off‑target effects.
With these combined assets, we believe our patent 
estate today is one of the most useful, most 
functional portfolios in the RNAi field and we believe 
it will provide us with the opportunity to actively 
pursue all our areas of interest.
Financial
Silence successfully strengthened its financial 
position through the completion of two financings 
in 2009 and early 2010 that generated proceeds 
of approximately £17.7m (gross). This funding 
provided cash resources that will support the 
Company’s operations into the second quarter 
of 2011. This is without taking into account any 
milestone or other receipts that the Company 
believes it could receive in 2010.
Revenue
Revenue generated in the year declined to £1.72m 
in 2009 from £2.21m in 2008. The decrease 
in revenue was primarily attributable to receiving 
milestone income from previous deals in 2008 
which did not arise in 2009.
Administrative expenses
Administrative expenses during the year increased 
to £4.20m in 2009 from £3.29m in 2008. 
The increase in administrative expenses is 
primarily attributed to costs incurred in respect 
of the acquisition of Intradigm subsequent 
to the year end.
Research and development expenses
Research and development expenses during 
the year decreased to £5.07m in 2009 from 
£6.71m in 2008. The decrease in research 
and development expense is primarily attributed 
to the Group having incurred substantial 
pre‑clinical development costs in 2008 prior 
to the commencement of its clinical trials 
of Atu027 which commenced in 2009.
Interest
Interest income fell from £0.25m in 2008 to 
less than £0.1m in 2009 due to lower average 
balances on deposit and the marked fall 
in interest rates during 2008 and 2009.
 in the 
enablement of clinical development 
of RNAi therapeutic candidates.
“ Silence successfully 
strengthened its 
financial position 
through the 
completion of two 
financings in 2009 
and early 2010 that 
generated proceeds 
of approximately 
£17.7m (gross). ”  09
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
Taxation
The taxation credit arises through the availability 
of UK R&D tax credits in respect of some of 
the Group’s research and development costs.
Liquidity, cash, cash equivalents and money 
market investments
The Group’s cash position at year‑end was £1.13m. 
A further £15.0m (gross) was raised shortly after 
the year‑end through an institutional placing that 
closed in January 2010. At the end of 2008, 
Silence had cash of £3.35m. 
The net cash outflow from operating activities was 
£4.65m against an operating loss of £7.55m 
primarily reflecting the impact of changes in 
other working capital of £1.6m and of non‑cash 
items such as depreciation, amortisation and 
share option charges of £1.0m.
Summary and outlook
I’d like to conclude by reviewing the rationale 
for the recent merger and the subsequent goals 
we aim to achieve.
In setting out to combine these two companies, 
our objective was to dramatically change the 
competitive landscape in the field of RNAi 
therapeutics. While other companies in the 
sector may claim leadership, this merger created 
one of the most sophisticated platforms in RNAi 
therapeutic development. As a result of this merger, 
Silence now holds a powerful and strategic position 
in the three areas we believe are critical to building, 
protecting and commercialising RNAi therapeutics: 
proprietary delivery technologies, potent siRNA 
sequences and innovative siRNA structural features.
This unique combination of technology has created 
an unparalleled technology platform that we believe 
will drive many of the most critical advances in 
the field. Perhaps most exciting about the merger 
is the powerful range of RNAi delivery technology 
solutions possessed by the new Company. The most 
significant hurdle to overcome in realisation of the 
vast potential of RNAi therapeutics is that of enabling 
safe and effective delivery of siRNA payloads. 
By combining the expertise of both Intradigm 
and Silence, we now have one of the industry’s 
most comprehensive and versatile delivery 
technology platforms, providing Silence with 
unmatched potential to develop delivery 
solutions that can be tailored to address 
various therapeutic requirements.
Beyond our technology platform, Silence is 
a clear leader in the enablement of clinical 
development of RNAi therapeutic candidates. 
At present, we believe that at least half of the 
siRNA programmes currently in clinical trials 
worldwide are based on Silence’s technology, 
representing the significant impact that our 
technology platform has within the sector. 
This impressive pipeline of products not only 
validates the strength of Silence’s technology, 
it also validates the team of researchers that has 
guided the development path. 
In summary, the rationale driving this merger 
was to combine the strength of two innovative 
entities to create a new leadership in RNAi 
therapeutic development. With the transaction 
complete, it is now our task to establish a path 
that allows us to optimise our resources and 
efficiently advance our development programmes 
and clinical efforts. To this end, we recently 
announced a restructuring of the Company 
to focus research in Berlin, and business 
operations in Palo Alto. We will continue 
to evaluate the most beneficial strategies 
to address the challenges ahead.
In closing, I wish to express my sincere appreciation 
to our dedicated employees and the shareholders 
who support our Company. In the coming year, 
we will continue to work diligently to advance 
our groundbreaking science and to continue 
to build shareholder value.
Thank you for your continued support 
of Silence Therapeutics. 
Philip Haworth PhD
Chief Executive Officer Silence Therapeutics plc Annual report and accounts 2009
10
Board of Directors
Jerry Randall
Non-executive Chairman
Mr Randall is a qualified Chartered Accountant. Most recently he was chief financial officer of Sinclair 
Pharmaceuticals plc, which he joined in 2000 as part of a management buy‑in team. Prior to this, 
Mr Randall worked in corporate finance with Gambit Corporate Finance and had previously been 
involved in two other buy‑ins. He acted as adviser to both private and quoted companies between 1993 
and 2000, in both the capacity of nominated adviser and in practice with KPMG. During this period, 
he was involved in a number of flotations and transactions on the Official List, Unlisted Securities 
Market and the Alternative Investment Market, as well as raising private equity.
Audit Committee 
Assisting Board oversight of accounting and 
financial reporting processes and the audits 
of the Company’s financial statements. 
  Jerry Randall (Chairman)
  David U’Prichard
Nomination Committee 
Recommending to the Board those persons 
to be nominated for election as Directors at 
any shareholders meeting. 
  David U’Prichard
  Annette Clancy
  David Mack
Remuneration Committee 
Assisting the Board in the discharging of 
its responsibilities related to remuneration 
of the Company’s Executive officers. 
  Annette Clancy (Chairman)
  Jamie Topper
  David U’Prichard
  David Mack
  Jerry Randall
Committee composition
Dr Phil Haworth
Chief Executive Officer
Dr Haworth was appointed Chief Executive Officer of Silence Therapeutics in January 2010 following 
the Company’s merger with Intradigm Corporation. Prior to this role, Dr Haworth served as chief executive 
officer of Intradigm, following his tenure as the company’s vice president of business development. 
He joined Intradigm in 2007, having spent the previous 15 years in senior business development 
roles at several leading biotechnology companies including Genencor International, COR Therapeutics 
and Affymax/Affymetrix, among others. In these positions, he led the identification and negotiation of 
numerous collaborative and licensing agreements with a range of global and regional pharmaceutical 
companies. He most recently served as vice president, business development at Codexis, Inc. He possesses 
deep deal‑ making expertise that spans establishing discovery and development partnerships, technology 
and product in‑ and out‑licensing, mergers and acquisitions, and financing support. Dr Haworth 
earned his JD from Stanford University Law School and his PhD in biochemistry from the University 
of Manchester in the UK. 
Max Herrmann
Chief Financial Officer and Company Secretary
Mr Herrmann was appointed Chief Financial Officer of Silence Therapeutics in May 2010. He is 
a qualified Chartered Accountant and possesses more than 20 years of biotechnology and pharmaceutical 
industry experience having held key management positions with leading development stage companies, 
as well as several investment banks. Prior to joining Silence, Mr Herrmann served as chief financial 
officer of Intercytex Group plc, a publicly traded company focused on the emerging area of regenerative 
medicine. Before joining Intercytex, he spent over ten years as a sell‑side equity analyst, most recently 
as managing director and head of European pharmaceutical and biotechnology research at ING. 
He has also held the position of financial controller for US‑based Onyx Pharmaceuticals Inc. and 
currently serves on the boards of Regenerative Medicine Assets Limited, as well as the company’s 
subsidiaries Intercytex Ltd and Axordia Ltd. 11
Silence Therapeutics plc Annual report and accounts 2009
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Corporate
governance
Financial
statements
Annette Clancy
Non-executive Director
Ms Clancy has had a distinguished career spanning 30 years with GlaxoSmithKline (GSK). She has 
15 years’ experience in Business Development, leading GSK’s global T ransactions and Alliance Management 
teams for the past three years, and during her tenure she and her team have been responsible for concluding 
a large number of research, development and commercial business collaborations on behalf of GSK. 
Prior to her role in Business Development, Ms Clancy held a number of positions in Clinical Research, 
R&D project management and Commercialisation. Ms Clancy has a BSc (Hons) Pharmacology from 
Bath University.
Dr David Mack
Non-executive Director
Dr Mack is a director at Alta Partners where he led the investment in Angiosyn as a director and acting CEO 
(acquired by Pfizer in 2005). He joined Intradigm’s board in May 2006 and served on that board until 
the merger with Silence Therapeutics. He is currently on the board of directors of Aerie Pharmaceuticals, 
Ceregene and Proacta. Prior to Alta, Dr Mack co‑founded and served as Vice President of Genomics 
Research at Eos Biotechnology (acquired by Protein Design Labs in 2003). From 1995 to 1997, 
he served at Affymetrix as head of cancer biology where he oversaw the development and application 
of DNA array technology in the areas of oncology and inflammation. He was also a pivotal member 
of the Polymerase Chain Reaction (PCR) invention group at Cetus (now Chiron) in the mid 1980s. 
Dr Mack received his PhD in 1992 from the University of Chicago. 
Dr James Topper
Non-executive Director
Dr Topper is a general partner at Frazier Healthcare Ventures’ Palo Alto office and was the chairman 
of the board of Intradigm from May 2006 to the date of the merger with Silence Therapeutics. Since joining 
Frazier Healthcare in 2003, Dr Topper has led several biopharma investments including Arête Therapeutics, 
Cotherix, and MacuSight. Dr Topper is also an advisory board member to the Harvard‑Partners Center 
for Genetics and Genomics. Prior to joining Frazier Healthcare, he served as head of the cardiovascular 
research and development franchise at Millennium Pharmaceuticals and ran Millennium San Francisco 
(formerly COR Therapeutics). Prior to the merger of COR and Millennium, he served as the vice president 
of biology at COR and was responsible for managing all of its research activities. Dr Topper received 
his MD and PhD in Biophysics from Stanford University School of Medicine in 1991. He continues to 
hold an appointment as a Clinical Assistant Professor of Medicine at Stanford University.
Dr David U’Prichard
Non-executive Director
Prior to joining the Board of Silence Therapeutics, Dr David U’Prichard was chief executive officer 
and a member of the board of directors of 3‑Dimensional Pharmaceuticals, Inc., Yardley PA (3DP) from 
1999 to 2003. During that time he took 3DP public and secured major collaborations with Bristol‑Myers 
Squibb and Johnson & Johnson. In March 2003, 3DP became a part of Johnson & Johnson Pharmaceutical 
R&D. From 1997 to 1999, Dr U’Prichard served as chairman of research and development at SmithKline 
Beecham, where he oversaw the entry of approximately ten compounds into global development; 
four compounds into Phase III trials and six compounds into early clinical trials. Additionally, he was 
involved in several major restructuring efforts at the company. Prior to SmithKline Beecham, Dr U’Prichard 
worked for ICI/Zeneca from 1986 to 1997, as executive vice president and international research director 
from 1994 to 1997. Silence Therapeutics plc Annual report and accounts 2009
12
Directors’ report
year ended 31 December 2009
The Directors present their report and the financial statements for the year ended 31 December 2009.
Review of the business and future developments
The Group carries out research and development of pharmaceutical products. In particular the Group is focusing on the development of its RNAi 
technology, which is currently moving from the pre‑clinical into clinical development phase. The Group’s key performance indicators are the cash 
position in relation to cash flow, the expenditure on research and development activities and the development milestones reached, together with the 
signing of research collaborations and licences to bring in both development partners and revenues. Details of the financial performance, including 
comments on the cash position and research and development expenditure, are given in the financial section of the Chief Executive’s review on 
pages 8 and 9. The product development pipeline is also shown above with a briefing on the Group’s technology. The Chairman’s statement provides 
details of the Group’s progress during the year against all its performance targets. The Chief Executive’s review describes the research and development 
activity during the year as well as outlining future planned developments. 
Post balance sheet events
A description of post balance sheet events is set out in note 26 to the financial statements.
Results and dividends
The Group recorded a loss for the year before taxation of £7,470,597 (2008: £7,434,641). Further details are given in the preceding Financial review. 
The Group is not yet in a position to pay a dividend and the loss for both periods has been added to the accumulated deficit on reserves.
Directors
The Directors who served at any time during the year were:
Chairman
I G Ross 
Executive Directors
J M Davies
Non‑executive Directors
J L Curnock Cook 
A Clancy 
J A P Randall 
H R P Reynolds 
D C U’Prichard 
B O Wetzel
The interests of the Directors in the share options of the Company are set out in note 18 to the financial statements. 
Since the year end, on 5 January 2010 P Haworth, J Topper, and D Mack were appointed to the Board and on 26 February 2010, I G Ross and J M Davies 
resigned. M Herrmann was appointed to the Board in May 2010.
Substantial interests
At 31 March 2010 the Company had been informed of the following substantial interests of over 3% of the issued share capital of the Company:
       Percentage  
       of issued 
       share capital 
      Number %
Frazier Healthcare Ventures     27,265,465 9.74%
ACP Capital     25,356,422 9.06%
Fidelity Investments     22,753,009 8.13%
Gartmore Investment Ltd     19,477,919 6.96%
Lilly Ventures     16,747,951 5.98%
Neue Bank, Vaduz     10,023,270 3.58%
Roche Finance     8,515,906 3.04%
Corporate governance
The Board meets regularly and has ultimate responsibility for the management of the Group and sub‑committees, comprising of Non‑executive Directors, 
meet as and when required to deal with remuneration and audit matters. 13
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
Corporate governance continued
Committee structure
Remuneration
A Clancy (Chairman), J A P Randall, D C U’Prichard, D Mack and J Topper
Audit
J A P Randall (Chairman) and D C U’Prichard
Nominations and Governance Committee
D C U’Prichard (Chairman), A Clancy and D Mack
Remuneration Committee
The Group has established a Remuneration Committee comprising five Non‑executive Directors to determine and review the emolument packages of 
the Directors of both the parent and subsidiary companies. The committee meets at least twice a year and is responsible for setting the Group’s overall 
policy on Executive remuneration and employment conditions, including setting the specific remuneration, benefits and terms of employment for each 
Executive Director.
The Board of Directors has considered the Remuneration Committee’s proposals in respect of the remuneration of the Directors and senior Executives 
and has accepted them without substantial revision.
Audit Committee
The Board seeks to present a balanced and understandable assessment of the Group’s position and prospects in all interim, final and price‑sensitive 
reports and information required to be presented by statute.
The Audit Committee comprises two Non‑executive Directors and its terms of reference include keeping under review the scope and results of the external 
audit and its cost‑effectiveness. The committee reviews the independence and objectivity of the external auditors, including the nature and extent of non‑audit 
services supplied by them to the Group. 
Shareholder communications
The Company uses its corporate website (www.silence‑therapeutics.com) to ensure that the latest announcements, press releases and published financial 
information are available to all shareholders and other interested parties.
The AGM is used to communicate with both institutional shareholders and private investors and all shareholders are encouraged to participate. Separate 
resolutions are proposed on each issue so that they can be given proper consideration and there is a resolution to approve the Annual report and accounts. 
The Company counts all proxy votes and will indicate the level of proxies lodged on each resolution after it has been dealt with by a show of hands.
Compliance with BIA Code
The Group is a member of the BioIndustry Association (BIA) and has complied with the BIA code of best practice throughout the year. The BIA code consists 
of principles and provisions relating to corporate governance, access to external advice, release of sensitive information and public announcements concerning 
the Group’s products and technology. The Code, which is obligatory for members of the BIA, is designed to operate with reference to the particular 
circumstances of biotechnology companies.
Directors’ responsibilities for the financial statements
The Directors are responsible for preparing the Annual report and financial statements in accordance with applicable law and regulations. Company law 
requires the Directors to prepare financial statements for each financial year that give a true and fair view of the state of affairs of the Company and the Group 
and of the profit or loss of the Group for the period.
The financial statements for the Group are prepared in accordance with International Financial Reporting Standards (IFRSs) as adopted by the European Union 
and the Board has also elected to prepare financial statements for the Company in accordance with IFRSs.
In preparing the financial statements, the Directors are required to:
  select suitable accounting policies and then apply them consistently;
  make judgements and estimates that are reasonable and prudent;
  state whether applicable IFRS have been followed, subject to any material departures disclosed and explained in the financial statements; and
  prepare the financial statements on the going concern basis unless it is inappropriate to presume that the Company will continue in business.
The Directors are responsible for keeping adequate accounting records that disclose with reasonable accuracy at any time the financial position of the 
Company and enable them to ensure that the financial statements comply with the Companies Act 2006. They are also responsible for safeguarding 
the assets of the Company and for taking reasonable steps for the prevention and detection of fraud and other irregularities.
Insofar as the Directors are aware:
  there is no relevant audit information of which the Company’s auditors are unaware; and
  the Directors have taken all steps that they ought to have taken to make themselves aware of any relevant audit information and to establish that 
the auditors are aware of that information.
The Directors are responsible for the maintenance and integrity of the corporate and financial information included on the Company’s website. Legislation 
in the United Kingdom governing the preparation and dissemination of the financial statements may differ from legislation in other jurisdictions. Silence Therapeutics plc Annual report and accounts 2009
14
Directors’ report continued
year ended 31 December 2009
Risk factors
The Group’s principal activity is biotechnology research and development. As with any business in this sector, there are risks and uncertainties relevant 
to the Group’s business. Certain of these risk factors affect the majority of businesses, some are common to businesses in the biotechnology sector 
and others are more specific to the Group.
Risks common to most businesses
  Failure to maintain legal and regulatory compliance.
  New accounting standards causing a material adverse impact on reported financial results.
  Failure to balance product portfolio against market projections and demands.
  Increasing cost and decreasing availability of insurance.
  Lack of control over external economic factors affecting business.
  Unforeseen events which would be classified as force majeure, e.g. fire, flood, loss of utilities.
  Inability to access sufficient resources to trade as a going concern. 
Risks applicable to the biotechnology sector and the Group
Clinical and regulatory risk
  The nature of pharmaceutical development is such that drug candidates may not be successful due to an inability to demonstrate in a timely manner 
the necessary safety and efficacy in a clinical setting to the satisfaction of appropriate regulatory bodies, such as the Food and Drug Administration (FDA) 
in the US and the European Medicines Agency (EMEA) in Europe. The Group will have limited control over the type and cost of trial required to obtain 
regulatory approval. 
  The Group will rely on third parties to conduct clinical trials. If these third parties do not successfully carry out their contractual duties or meet expected 
deadlines, the programmes of the Group may be delayed or the Group may not be able to obtain regulatory approval for its products. Any failure or 
delay of projects in development or clinical trials could have an adverse effect on the business. 
  With the prime focus of the Group being on such a new area of technology, there can be no assurance that the Group’s products will receive and maintain 
regulatory approval. 
Product development risk
  The Group is involved at the leading edge of a revolutionary technology. Within the pharmaceutical sector more drugs fail in development than progress 
to market and there is no guarantee that the Group will be able to successfully develop this new technology or bring any of the drug candidates 
it is developing to market. Further, the drugs that the Group does bring to market may not be commercially successful.
  The Group has no track record of successful development and registration of any product and will need to acquire or gain access to relevant additional expertise.
  In order to progress the Group’s product development plans it may be desirable or necessary to find collaborators on certain projects. The Group cannot 
guarantee that it will be able to find and maintain suitable collaborators under acceptable terms, or that, once found, such collaborators will devote 
sufficient resources to the collaboration to make it commercially successful. 
  The Group’s suppliers may encounter unexpected difficulties in the design and construction of manufacturing processes and the scale‑up of production 
to viable commercial levels or may otherwise be unable to supply materials to the Group in a timely manner. 
  Competition for employees in the biotechnology sector may lead to increased costs or decreased availability of staff. As a result, the Group may 
be unable to recruit or retain certain important employees. This could weaken the Group’s scientific and management capabilities and could delay 
or halt the development of products and technologies. 
Competition risk
  RNAi technology is attracting increased interest and with that is increased competition. Competitors in the sector may have greater financial, human 
and other resources and more experience to develop competing products or technology.
  Many companies are trying to develop competing technologies and one or more of these may restrict the potential commercial success of the Group’s 
products or render them obsolete. 
  Increasing competition may also have an adverse effect on the timing or scale of commercialisation of the Group’s technology. 
Intellectual property risk
  Intellectual property issues from challenges by others or lack of protection for its own products may negatively impact the Group. Other companies 
may have or develop intellectual property that restricts the Group’s freedom of use or imposes high additional costs to obtain licences. 
  The Group may be unable to successfully establish and protect its intellectual property which is significant to the Group’s competitive position.
  The Group’s intellectual property may become invalid or expire before its products are successfully commercialised. 15
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
Risk factors continued
Risks applicable to the biotechnology sector and the Group continued
Financial risk
  There are very high costs of product development, where products have lead times to market of many years.
  The lack of a substantial recurrent revenue stream and the significant resources needed for ongoing investment in its R&D pipeline require the Group 
to gain access to additional funding from licensing, capital markets or elsewhere. There can be no assurances that such funding will be achieved 
on favourable terms, if at all. 
  Additional funding will be required to give the Group time to reach profitability. If the Group is unable to raise those funds, there may be insufficient 
finance for product development or operations and consequent delay, reduction or elimination of development programmes could result. 
  The Group has a small portfolio of products. Success or failure with individual products could have a significant impact on the share price. This in turn 
may make it difficult for the Group to continue funding its development programme. 
  The Group may be unable to secure adequate insurance at an acceptable cost.
This list should not be considered an exhaustive statement of all potential risks and uncertainties.
Going concern
After making enquiries, the Directors have a reasonable expectation that the Group has adequate resources to continue in operational existence for the 
foreseeable future. Further details are given in note 2.3 to the financial statements. For this reason the Directors continue to adopt the going concern 
basis in preparing the financial statements.
Payment of creditors
It is the Group’s policy to make payments to creditors in accordance with individually agreed terms, generally within 30 days either of the invoice date 
or from the end of the month the invoice was raised. Using the method set out in the Companies Act, the ratio for the Group of trade creditors at the year 
end to total costs was 47 days (2008: 29 days). 
On behalf of the Board
Jerry Randall
Chairman 
17 May 2010 Silence Therapeutics plc Annual report and accounts 2009
16
Independent auditors’ report
to the members of Silence Therapeutics plc
We have audited the financial statements of Silence Therapeutics plc for the year ended 31 December 2009 which comprise the Consolidated income 
statement, the Consolidated statement of comprehensive income, the Consolidated balance sheet, the Consolidated statement of changes in equity, 
the Company balance sheet, the Company statement of changes in equity, the Consolidated and Company cash flow statement and the related notes. 
The financial reporting framework that has been applied in their preparation is applicable law and International Financial Reporting Standards (IFRSs) 
as adopted by the European Union and, as regards the parent company financial statements, as applied in accordance with the provisions of the 
Companies Act 2006. This report is made solely to the Company’s members, as a body, in accordance with Chapter 3 of Part 16 of the Companies Act 2006. 
Our audit work has been undertaken so that we might state to the Company’s members those matters we are required to state to them in an auditors’ 
report and for no other purpose. To the fullest extent permitted by law, we do not accept or assume responsibility to anyone other than the Company 
and the Company’s members as a body, for our audit work, for this report, or for the opinions we have formed.
Respective responsibilities of Directors and auditors
As explained more fully in the Directors’ responsibilities statement, set out on page 13, the Directors are responsible for the preparation of the financial 
statements and for being satisfied that they give a true and fair view. Our responsibility is to audit the financial statements in accordance with applicable 
law and International Standards on Auditing (UK and Ireland). Those standards require us to comply with the Auditing Practices Board’s (APB’s) Ethical 
Standards for Auditors.
Scope of the audit of the financial statements
A description of the scope of an audit of financial statements is provided on the APB’s website at www.frc.org.uk/apb/scope/UKNP .
Opinion on financial statements
In our opinion:
   the Group financial statements give a true and fair view of the state of the Group and of the parent company’s affairs as at 31 December 2009 
and of the Group’s loss for the year then ended; 
  the Group financial statements have been properly prepared in accordance with IFRS as adopted by the European Union; 
   the parent company financial statements have been properly prepared in accordance with IFRS as adopted by the European Union and as applied 
in accordance with the provisions of the Companies Act 2006; and
  the financial statements have been prepared in accordance with the requirements of the Companies Act 2006.
Emphasis of matter – going concern
In forming our opinion on the financial statements, which is not qualified, we have considered the adequacy of disclosures made in note 2.3 of the 
financial statements concerning the ability of the Company to continue as a going concern. The Group made a loss for the year of £7.5m and had net 
assets of £8.9m at 31 December 2009. As explained in note 2.3, there are uncertainties regarding the Group’s ability to access additional funding through 
grants, milestone and licence fee payments, relating to either new or existing agreements, to meet working capital requirements. 
These conditions explained in note 2.3 to the financial statements indicate the existence of a material uncertainty which may cast significant doubt about 
the Company’s ability to continue as a going concern. The financial statements do not include any adjustments that would result if the Company were 
unable to continue as a going concern.
Opinion on other matters prescribed by the Companies Act 2006
In our opinion the information given in the Directors’ report for the financial year for which the financial statements are prepared is consistent with the 
financial statements.
Matters on which we are required to report by exception
We have nothing to report in respect of the following matters where the Companies Act 2006 requires us to report to you if, in our opinion:
   adequate accounting records have not been kept by the parent company, or returns adequate for our audit have not been received from branches 
not visited by us; or
  the parent company financial statements are not in agreement with the accounting records and returns; or
  certain disclosures of Directors’ remuneration specified by law are not made; or
  we have not received all the information and explanations we require for our audit.
Christopher Smith
Senior Statutory Auditor
for and on behalf of Grant Thornton UK LLP
Statutory Auditor, Chartered Accountants
London
17 May 2010 17
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
Consolidated income statement
year ended 31 December 2009
      2009 2008 
     Note £ £
Revenue    3 1,723,289 2,208,699
Research and development costs     (5,073,333) (6,712,032)
Gross loss     (3,350,044) (4,503,333)
Administrative expenses     (4,204,371) (3,288,304)
Operating loss    5 (7,554,415) (7,791,637)
Finance income    7 46,104 356,996
Loss for the year before taxation     (7,508,311) (7,434,641)
Taxation credit for the year    8 37,714 —
Loss for the year after taxation     (7,470,597) (7,434,641)
Loss per share (basic and diluted)    9 (5.55)p (6.20)p
The accompanying accounting policies and notes form an integral part of these financial statements.
 
Consolidated statement 
of comprehensive income
year ended 31 December 2009
 
      2009 2008 
      £ £
Loss for the year after taxation     (7,470,597) (7,434,641)
Other comprehensive income:
Exchange differences arising on consolidation of foreign operations    (410,482) 2,654,895
Total comprehensive income for the year     (7,881,079) (4,779,746)
The accompanying accounting policies and notes form an integral part of these financial statements. Silence Therapeutics plc Annual report and accounts 2009
18
Consolidated balance sheet
at 31 December 2009
      2009 2008 
     Note £ £
Non‑current assets
Property, plant and equipment    10 376,676 535,909
Goodwill    11 8,130,972 8,611,087
Other intangible assets    12 736,117 812,696
      9,243,765 9,959,692
Current assets
Trade and other receivables    14 560,190 998,702
Current tax assets     59,198 70,000
Cash and cash equivalents    15 1,131,146 3,350,187
      1,750,534 4,418,889
Liabilities – current
Trade and other payables    16 2,103,144 934,601
      2,103,144 934,601
Net assets     8,891,155 13,443,980
Equity
Share capital    18 1,350,334 1,199,134
Capital reserves    19 49,810,071 47,010,414
Translation reserve     2,881,007 3,291,489
Retained loss     (45,150,257) (38,057,057)
Total equity     8,891,155 13,443,980
The financial statements were approved by the Board of Directors on 17 May 2010.
Jerry Randall
Chairman
The accompanying accounting policies and notes form an integral part of these financial statements. 19
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
Consolidated statement of changes in equity
year ended 31 December 2009
   Share Capital Translation Retained 
   capital reserves reserve loss Total 
   £ £ £ £ £
At 1 January 2008  1,198,835 46,465,165 636,594 (30,624,834) 17,675,760
Recognition of share‑based payments  — 544,158 — — 544,158
Transfer upon:
 – exercise of options in year  — (1,687) — 1,687 —
 – lapse of vested options in year  — (731) — 731 —
Shares issued in the year  299 3,509 — — 3,808
Transactions with owners  299 545,249 — 2,418 547,966
Loss for the year ended 31 December 2008  — — — (7,434,641) (7,434,641)
Other comprehensive income
Exchange differences arising on consolidation of foreign operations — — 2,654,895 — 2,654,895
Total comprehensive income for the year  — — 2,654,895 (7,434,641) (4,779,746)
At 1 January 2009  1,199,134 47,010,414 3,291,489 (38,057,057) 13,443,980
Recognition of share‑based payments  — 661,704 — — 661,704
Transfer upon:
– exercise of options in year  — (4,514) — 4,514 —
– lapse of vested options in year  — (372,883) — 372,883 —
Shares issued in the year  151,200 2,515,350 — — 2,666,550
Transactions with owners  151,200 2,799,657 — 377,397 3,328,254
Loss for the year ended 31 December 2009  — — — (7,470,597) (7,470,597)
Other comprehensive income
Exchange differences arising on consolidation of foreign operations — — (410,482) — (410,482)
Total comprehensive income for the year  — — (410,482) (7,470,597) (7,881,079)
At 31 December 2009  1,350,334 49,810,071 2,881,007 (45,150,257) 8,891,155 Silence Therapeutics plc Annual report and accounts 2009
20
Company balance sheet
at 31 December 2009
      2009 2008 
     Note £ £
Non‑current assets
Investment in subsidiary undertakings    13 23,494,482 19,917,264
Current assets
Trade and other receivables     91,236 65,747
Cash and cash equivalents    15 358,256 1,914,188
      449,492 1,979,935
Liabilities – current
Trade and other payables    16 1,185,705 146,774
      1,185,705 146,774
Net assets     22,758,269 21,750,425
Equity
Share capital    18 1,350,334 1,199,134
Capital reserves    19 49,626,155 46,826,498
Retained loss     (28,218,220) (26,275,207)
Total equity     22,758,269 21,750,425
The financial statements were approved by the Board of Directors on 17 May 2010.
Jerry Randall
Chairman
The accompanying accounting policies and notes form an integral part of these financial statements. 21
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
Company statement of changes in equity
year ended 31 December 2009
    Share Capital Retained 
    capital reserves loss Total 
    £ £ £ £
At 1 January 2008   1,198,835 46,281,249 (24,233,386) 23,246,698
Loss for the year ended 31 December 2008   — — (2,041,821) (2,041,821)
Recognition of share‑based payments   — 544,158 — 544,158
Transfer upon: 
 – exercise of options in year   — (1,687) — (1,687)
 – lapse of vested options in year   — (731) — (731)
Shares issued in the year   299 3,509 — 3,808
Movement in the year   299 545,249 (2,041,821) (1,496,273)
At 31 December 2008   1,199,134 46,826,498 (26,275,207) 21,750,425
Loss for the year ended 31 December 2009   — — (2,313,382) (2,313,382)
Recognition of share‑based payments   — 661,704 — 661,704
Transfer upon:
 – exercise of options in year   — (4,514) — (4,514)
 – lapse of vested options in year   — (372,883) 370,369 (2,514)
Shares issued in the year   151,200 2,515,350 — 2,666,550
Movement in the year   151,200 2,799,657 (1,943,013) 1,007,844
At 31 December 2009   1,350,334 49,626,155 (28,218,220) 22,758,269 Silence Therapeutics plc Annual report and accounts 2009
22
Cash flow statements
year ended 31 December 2009
  Group  Company
    2009 2008 2009 2008 
    £ £ £ £
Cash flow from operating activities
Loss before taxation   (7,508,311) (7,434,641) (2,313,382) (2,041,821)
Adjustments for:
Depreciation charges   150,293 116,489 — —
Amortisation charges   220,658 306,916 — —
Loss on sale of property, plant and equipment   19,577 307 — —
Charge for the year in respect of share‑based payments    661,704 544,158 318,027 125,353
Foreign exchange movement   198,717 73,410 — —
(Reduction)/increase in impairment provision against loan to subsidiary  — — (140,667) 596,533
Recovery of loan provided for in previous years   — (31,000) — (31,000)
Finance income   (46,104) (253,634) (43,971) (198,464)
    (6,306,466) (6,677,995) (2,179,993) (1,549,399)
Decrease/(increase) in trade and other receivables   438,512 668,891 (25,489)  (65,747)
Increase/(decrease) in trade and other payables   1,168,543 (1,032,708) 1,038,931  146,774 
Cash (absorbed) by operations   (4,696,411) (7,041,812) (1,166,551) (1,468,372)
Taxation received   48,516 60,000 — —
Net cash outflow from operating activities   (4,647,895) (6,981,812) (1,166,551)  (1,468,372)
Cash flow from investing activities
Investment in subsidiary undertakings   — — (3,409,986) (6,308,552)
Reduction/(increase) in loans to subsidiary undertakings   — — 310,084 (109,384)
Recovery of loan made in previous years   — 31,000 — 31,000
Finance income   46,104 253,634 43,971 198,464
Additions to property, plant and equipment   (36,648) (135,584) — —
Additions to intangible assets   (188,494) (135,752) — —
Net cash (used in)/generated from investing activities   (179,038) 13,298 (3,055,931) (6,188,472)
Cash flow from financing activities
Proceeds from issue of share capital   2,666,550 3,808 2,666,550 3,808
Decrease in cash and cash equivalents   (2,160,383) (6,964,706) (1,555,932) (7,653,036)
Cash and cash equivalents at start of year   3,350,187 10,174,389 1,914,188 9,567,224
Net decrease in the year   (2,160,383) (6,964,706) (1,555,932) (7,653,036)
Effect of exchange rate fluctuations on cash held   (58,658) 140,504 — —
Cash and cash equivalents at end of year   1,131,146 3,350,187 358,256 1,914,188
Cash and cash equivalents includes:
Instant access bank accounts   1,131,146 3,350,187 358,256 1,914,188
The accompanying accounting policies and notes form an integral part of these financial statements. 23
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
Notes to the financial statements
year ended 31 December 2009
1. General information
1.1 Group
Silence Therapeutics plc (“Silence Therapeutics” or “the Company”) and its subsidiaries (together “the Group”) are primarily involved in the research 
and development of novel pharmaceutical products. Silence Therapeutics plc, a public limited company incorporated and domiciled in England, is the Group’s 
ultimate parent company. The address of Silence Therapeutics’ registered office is 22 Melton Street, London NW1 2EP and the principal place of business 
is The Royal Institution of Great Britain, 21 Albemarle Street, London W1S 4BS.
1.2 Company income statement
The Company has taken advantage of Section 408 of the Companies Act 2006 and has not included its own profit and loss account in these financial 
statements. The loss for the financial year dealt with in the accounts of the Company, including provision against the loans to and investment in subsidiary 
companies, amounted to £2,313,382 (2008: loss £2,041,821).
2. Principal accounting policies
2.1 Basis of preparation
The financial statements have been prepared in accordance with International Financial Reporting Standards (IFRS) as adopted by the EU and on the 
historical cost basis. 
The Group has not adopted the following new IFRS and International Accounting Standards (IAS) that have been issued but are not yet effective:
       Effective from:
IFRS 9 Financial Instruments      1 January 2013
IAS 24 (revised 2009) Related Party Disclosures      1 January 2011
IAS 32 (amendment to) Classification of Rights Issues      1 February 2010
IFRIC 19 Extinguishing Financial Liabilities with Equity Instruments     1 July 2010
IFRIC 14 (amendment to)  Prepayments of a Minimum Funding Requirement    1 January 2011
None of these are expected to have a significant impact on the financial statements.
The following standards, amendments and interpretations have been applied for the first time in the year under review:
   IAS 1 Presentation of Financial Statements (Revised 2007) requires presentation of a comparative balance sheet at the beginning of the first 
comparative period in some circumstances. Management considers that this is not necessary because the 2007 balance sheet is the same as 
that previously published.
   IFRS 8 Operating Segments replaces IAS 14 Segment Reporting and requires implementation of the Management Approach to reporting as operating segments.
The principal accounting policies adopted are set out below.
2.2 Basis of consolidation
The Group financial statements consolidate those of the Company and its controlled subsidiary undertakings drawn up to 31 December 2009. Control 
is achieved where the Company has the power to govern the financial and operating policies of the entity so as to obtain benefits from its activities.
The results of subsidiaries acquired or disposed of during the year are included in the consolidated income statement from the effective date of acquisition 
or up to the effective date of disposal.
Where necessary, adjustments are made to the financial statements of subsidiaries to bring accounting policies into line with those used for reporting 
the operations of the Group. All intra‑group transactions, balances, income and expenses are eliminated on consolidation. 
2.3 Going concern
The financial statements have been prepared on a going concern basis that assumes that the Group will continue in operational existence for 
the foreseeable future. 
The Group had a net cash outflow for 2009 of £2,160,383 and at 31 December 2009 had cash balances of £1.13m. In early January 2010, the Group 
acquired Intradigm Corporation and raised £15m (before costs). 
The Directors have reviewed the working capital requirements of the Group, which now comprises two research and development pharmaceutical 
companies, for the next twelve months and are confident that these can be met. The Directors have a reasonable expectation that further finances will 
become available during the course of the year through grants, milestone and licence fee payments, relating to either new or existing agreements. 
The Directors note that there is a material uncertainty as to the exact timing and source of these funds and that the failure to receive sufficient funding 
from these sources would cast significant doubt on the Group’s ability to continue as a going concern. The Directors have also taken a number of steps 
to reduce administration costs and to restrict the research and development expenditure to core areas pending the availability of additional funds.
The Directors consider that the continued adoption of the going concern basis is appropriate and the accounts do not reflect any adjustments that would 
be required if they were to be prepared on any other basis. Silence Therapeutics plc Annual report and accounts 2009
24
Notes to the financial statements continued
year ended 31 December 2009
2. Principal accounting policies continued
2.4 Business combinations
The acquisition of subsidiaries is accounted for using the purchase method. The cost of the acquisition is measured at the aggregate of the fair values, 
at the date of exchange, of assets given, liabilities incurred or assumed, and equity instruments issued by the Group in exchange for control of the acquiree, 
plus any costs directly attributable to the business combination. The acquiree’s identifiable assets, liabilities and contingent liabilities that meet the conditions 
for recognition under IFRS 3 are recognised at their fair values at the acquisition date. 
In arriving at the cost of acquisition, the fair value of the shares issued by the Company is taken to be the bid price of those shares at the date of issue. 
Where this figure exceeds the nominal value of the shares, the excess amount is treated as an addition to the share premium account. 
2.5 Goodwill
Goodwill arising on the acquisition of a subsidiary represents the excess of the cost of acquisition over the Group’s interest in the net fair value of the identifiable 
assets, liabilities and contingent liabilities of the subsidiary at the date of acquisition. Goodwill is initially recognised as an asset at cost and is subsequently 
measured at cost less any accumulated impairment losses.
On disposal of a subsidiary, the attributable amount of goodwill is included in the determination of the profit or loss on disposal.
2.6 Revenue recognition
The Group’s income consists of licence fees, milestone and option payments, grant income and fees from research and development collaborations. 
Income is measured at the fair value of the consideration received or receivable.
Licence fees, option and milestone payments are recognised in full on the date that they are contractually receivable in those circumstances where:
  the amounts are not time related; 
  the amounts are not refundable;
  the licensee has unrestricted rights to exploit the technology within the terms set by the licence; and
  the Group has no further contractual duty to perform any future services. 
Where such fees or receipts require future performance or financial commitments on behalf of the Group, the revenue is recognised pro rata to the services 
or commitments being performed. 
Revenues from work or other research and testing carried out for third parties are recognised when the work to which they relate has been performed. 
Government grants are dealt with as per note 2.7 below.
All time related receipts in respect of annual licence fees or similar technology access fees are recognised as revenue on a straight‑line basis over 
the period of the underlying contract.
2.7 Government grants
Government grants towards the cost of staff employed in research and development activities are recognised as income over the periods necessary 
to match them with the related costs. Grants amounting to £527,129 were recognised as revenue in the year ended 31 December 2009 (2008: £863,578). 
Government grants towards the cost of plant and equipment are treated as a reduction in the cost of the asset to which they relate. There were no such 
grants for the year ended 31 December 2009 (2008: £53,477).
There were no unfulfilled conditions or contingencies attaching to these grants.
2.8 Foreign currency translation
Silence Therapeutics’ consolidated financial statements are presented in Sterling (£), which is also the functional currency of the parent company. 
The individual financial statements of each Group entity are presented in the currency of the primary economic environment in which the entity operates 
(its functional currency).
In preparing the financial statements of the individual entities, transactions in currencies other than the entity’s functional currency (foreign currencies) 
are recorded at the rates of exchange prevailing on the dates of the transactions. At each balance sheet date, monetary items denominated in foreign 
currencies are retranslated at the rates prevailing on the balance sheet date. Non‑monetary items carried at fair value that are denominated in foreign 
currencies are retranslated at the rates prevailing on the date when the fair value was determined. 
Exchange differences arising on the settlement of monetary items, and on the retranslation of monetary items, are included in profit or loss for the period. 
When a gain or loss on a non‑monetary item is recognised directly in equity, any exchange component of that gain or loss is also recognised directly 
in equity. When a gain or loss on a non‑monetary item is recognised in profit or loss, any exchange component of that gain or loss is also recognised 
in profit or loss. 
For the purpose of presenting consolidated financial statements, the assets and liabilities of the Group’s foreign operations (including comparatives) 
are expressed in Sterling using exchange rates prevailing on the balance sheet date. Income and expense items (including comparatives) are translated 
at the actual exchange rates. Exchange differences arising, if any, are recognised in equity. Cumulative translation differences are recognised in profit 
or loss in the period in which the foreign operation is disposed of.
Goodwill and fair value adjustments arising on the acquisition of a foreign operation are treated as assets and liabilities of the foreign operation and translated 
at the closing rate. 25
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2. Principal accounting policies continued
2.9 Defined contribution pension funds
The Group pays contributions related to salary to certain UK employees’ individual pension schemes. The pension cost charged against profits represents 
the amount of the contributions payable to the schemes in respect of the accounting period. No separate provision is made in respect of non‑UK employees.
2.10 Property, plant and equipment
The Group holds no property assets.
All plant and equipment is stated in the accounts at its cost of acquisition less a provision for depreciation.
Depreciation is charged to write off the cost less estimated residual values of plant and equipment on a straight‑line basis over their estimated useful 
lives. All plant and equipment is estimated to have useful lives of between three and five years. Estimated useful lives and residual values are reviewed 
each year and amended if necessary.
2.11 Other intangible assets and research and development activities
Intellectual property rights
Other intangible assets include both acquired and internally developed intellectual property used in research and operations. These assets are stated 
at cost less amortisation. 
Acquired intellectual property rights are capitalised on the basis of the costs incurred to acquire the specific rights.
Internally generated intellectual property rights are recognised as intangible assets, stated at cost incurred to establish and maintain those rights, and are 
subject to the same subsequent measurement method as externally acquired intellectual property. However, until completion of the development project, 
the assets are subject to impairment testing only as described below. Amortisation commences upon completion of the asset.
Amortisation is applied to write off the cost less residual value of the intangible assets on a straight‑line basis over their estimated useful life. The principal 
rate used is 10% per annum. Amortisation is included within research and development costs.
Capitalisation of research and development costs
Costs associated with research activities are treated as an expense in the period in which they are incurred.
Costs that are directly attributable to the development phase of an internal project will only be recognised as intangible assets provided they meet 
the following requirements:
  an asset is created that can be separately identified;
  the technical feasibility exists to complete the intangible asset so that it will be available for sale or use and the Group has the intention and ability 
so to do;
  it is probable that the asset created will generate future economic benefits either through internal use or sale;
  sufficient technical, financial and other resources are available for completion of the asset; and
  the expenditure attributable to the intangible asset during its development can be reliably measured.
Careful judgement by the Group’s management is applied when deciding whether recognition requirements for development costs have been met. This 
is necessary as the economic success of any product development is uncertain and may be subject to future technical problems at the time of recognition. 
Judgements are based on the information available at each balance sheet date. 
To date, no development costs have been capitalised in respect of the internal projects other than costs directly associated with arising intellectual property 
rights on the grounds that the costs to date are either for the research phase of the projects or, if relating to the development phase, then the work so far 
does not meet the recognition criteria set out above. 
2.12 Impairment testing of goodwill, other intangible assets and property, plant and equipment
At each balance sheet date, the Group assesses whether there is any indication that the carrying value of any asset may be impaired. If any such indication 
exists, the recoverable amount of the asset is estimated in order to determine the extent of the impairment loss (if any). Where it is not possible to estimate 
the recoverable amount of an individual asset, the Group estimates the recoverable amount of the cash‑generating unit to which the asset belongs.
In the case of goodwill and any intangible asset with either an indefinite useful life or which is not yet ready for use, the Group tests for impairment 
at each balance sheet date.
For the purposes of assessing impairment, assets are grouped at the lowest levels for which there are separately identifiable cash flows (cash‑generating 
units). Goodwill is allocated to those cash‑generating units that are expected to benefit from synergies of the related business combination and represent 
the lowest level within the Group at which management controls the related cash flows. 
Individual assets or cash‑generating units that include goodwill and other intangible assets with an indefinite useful life, or those not yet available for use, 
are tested for impairment at least annually. All other individual assets or cash‑generating units are tested for impairment whenever events or changes 
in circumstances indicate that the carrying amount may not be recoverable.
An impairment loss is recognised for the amount by which the asset’s or cash‑generating unit’s carrying amount exceeds its recoverable amount. 
The recoverable amount is the higher of fair value, reflecting market conditions less costs to sell, and value in use, based on an internal discounted 
cash flow evaluation. Impairment losses recognised for cash‑generating units to which goodwill has been allocated are credited initially to the carrying 
amount of goodwill. Any remaining impairment loss is charged pro rata to the other assets in the cash‑generating unit.  Silence Therapeutics plc Annual report and accounts 2009
26
Notes to the financial statements continued
year ended 31 December 2009
2. Principal accounting policies continued
2.13 Investments in subsidiaries
Investments in subsidiaries comprise shares in the subsidiaries and loans from the Company. Investment in shares of the subsidiaries are stated at cost 
less provisions for impairment. Loans to subsidiaries are recorded at fair value.
2.14 Financial instruments
Financial assets and financial liabilities are recognised on the Group’s balance sheet when the Group becomes a party to the contractual provisions 
of the instrument.
Financial assets can be divided into the following categories: loans and receivables, financial assets at fair value through profit or loss, available‑for‑sale 
financial assets and held‑to‑maturity investments. Financial assets are assigned to the different categories by management on initial recognition, depending 
on the purpose for which the instruments were acquired. The designation of financial assets is re‑evaluated at every reporting date at which a choice 
of classification or accounting treatment is available.
Derecognition of financial instruments occurs when the rights to receive cash flows from investments expire or are transferred and substantially all 
of the risks and rewards of ownership have been transferred. An assessment for impairment is undertaken at least at each balance sheet date whether 
or not there is objective evidence that a financial asset or a group of financial assets is impaired.
Trade receivables
Trade receivables are measured at initial recognition at fair value plus, if appropriate, directly attributable transaction costs and are subsequently measured 
at amortised cost using the effective interest method. Appropriate allowances for estimated irrecoverable amounts are recognised in profit or loss when 
there is objective evidence that the asset is impaired. The allowance recognised is measured as the difference between the asset’s carrying amount 
and the present value of estimated future cash flows discounted at an effective interest rate computed at initial recognition.
Loans receivable
Loans receivable are non‑derivative financial assets with fixed or determinable payments that are not quoted in an active market. They arise when the Group 
or Company provides money directly to a debtor with no intention of trading the receivables. Loans receivable are measured at initial recognition at fair 
value plus, if appropriate, directly attributable transaction costs and are subsequently measured at amortised cost using the effective interest method, 
less provision for impairment. Any change in their value is recognised in profit or loss.
Cash and cash equivalents
Cash and cash equivalents comprise cash on hand and demand deposits that are readily convertible to a known amount of cash and are subject 
to an insignificant risk of change in value.
Financial liabilities and equity
Financial liabilities and equity instruments issued by the Group are classified according to the substance of the contractual arrangements entered into 
and the definitions of a financial liability and an equity instrument. A financial liability is a contractual obligation to either deliver cash or another financial 
asset to another entity or to exchange a financial asset or financial liability with another entity, including obligations which may be settled by the Group 
using its equity instruments. An equity instrument is any contract that evidences a residual interest in the assets of the Group after deducting all of its 
liabilities. The accounting policies adopted for specific financial liabilities and equity instruments are set out below.
Financial liabilities
At initial recognition, financial liabilities are measured at their fair value plus, if appropriate, any transaction costs that are directly attributable to the issue 
of the financial liability. After initial recognition, all financial liabilities are measured at amortised cost using the effective interest method.
Equity instruments
Equity instruments issued by the Group are recorded at the proceeds received net of direct issue costs.
2.15 Operating leases
Leases where substantially all the risks and rewards of ownership remain with the lessor are accounted for as operating leases and are accounted for 
on a straight‑line basis over the term of the lease and charged to the income statement.
2.16 Provisions
Provisions are recognised when the Group has a present obligation as a result of a past event and it is probable that the Group will be required to settle 
that obligation. Provisions are measured at the Directors’ best estimate of the expenditure required to settle the obligation at the balance sheet date 
and are discounted to present value where the effect is material. 
2.17 Share‑based payments
The Group issues equity‑settled share‑based payments to certain employees and advisers. Equity‑settled share‑based payments are measured at fair value 
(excluding the effect of non market‑based vesting conditions) at the date of grant. The fair value so determined is expensed on a straight‑line basis 
over the vesting period, based on the Group’s estimate of the number of shares that will eventually vest and adjusted for the effect of non market‑based 
vesting conditions.
Fair value is measured using a Binomial pricing model. The key assumptions used in the model have been adjusted, based on management’s best 
estimate, for the effects of non‑transferability, exercise restrictions and behavioural considerations. 27
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Financial
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2. Principal accounting policies continued
2.18 Equity 
Share capital is determined using the nominal value of shares that have been issued.
The share premium account includes any premiums received on the initial issuing of the share capital. Any transaction costs associated with the issuing 
of shares are deducted from the share premium account, net of any related income tax benefits.
The merger reserve represents the difference between the nominal value and the market value at the date of issue of shares issued in connection with 
the acquisition by the Group of an interest in over 90% of the share capital of another company.
Equity‑settled share‑based payments are credited to a share‑based payment reserve as a component of equity until related options or warrants are exercised.
Foreign currency translation differences are included in the translation reserve.
Retained loss includes all current and prior period results as disclosed in the income statement.
2.19 Taxation
The tax credit recognised in the income statement represents the sum of the tax currently payable or receivable and deferred tax.
The tax currently payable is based on taxable profit for the year. Taxable profit differs from profit as reported in the income statement because it excludes 
items of income or expense that are taxable or deductible in other years and it further excludes items that are never taxable or deductible. The Group’s 
liability for current tax is calculated using tax rates that have been enacted or substantively enacted by the balance sheet date.
Tax receivable arises from the UK legislation regarding the treatment of certain qualifying research and development costs, allowing for the surrender 
of tax losses attributable to such costs in return for a tax rebate.
Deferred tax is recognised on differences between the carrying amounts of assets and liabilities in the financial statements and the corresponding tax bases 
used in the computation of taxable profit, and is accounted for using the balance sheet liability method. Deferred tax liabilities are generally recognised 
for all taxable temporary differences and deferred tax assets are recognised to the extent that it is probable that taxable profits will be available against 
which deductible temporary differences can be utilised. Such assets and liabilities are not recognised if the temporary difference arises from initial 
recognition of goodwill or from the initial recognition (other than in a business combination) of other assets and liabilities in a transaction that affects 
neither the taxable profit nor the accounting profit.
Deferred tax liabilities are recognised for taxable temporary differences arising on investments in subsidiaries and associates, and interests in joint ventures, 
except where the Group is able to control the reversal of the temporary difference and it is probable that the temporary difference will not reverse 
in the foreseeable future.
The carrying amount of deferred tax assets is reviewed at each balance sheet date and reduced to the extent that it is no longer probable that sufficient 
taxable profits will be available to allow all or part of the asset to be recovered.
Deferred tax is calculated at the tax rates that are expected to apply in the period when the liability is settled or the asset realised. Deferred tax is charged 
or credited to profit or loss, except when it relates to items charged or credited directly to equity, in which case the deferred tax is also dealt with in equity.
Deferred tax assets and liabilities are offset when there is a legally enforceable right to set off current tax assets against current tax liabilities and when 
they relate to income taxes levied by the same taxation authority and the Group intends to settle its current tax assets and liabilities on a net basis.
2.20 Critical accounting judgements and key sources of estimation uncertainty
In the process of applying the entity’s accounting policies, management makes estimates and assumptions that have an effect on the amounts recognised 
in the financial statements. Although these estimates are based on management’s best knowledge of current events and actions, actual results may ultimately 
differ from those estimates.
The key assumptions concerning the future, and other key sources of estimation uncertainty at the balance sheet date, that have a significant risk of causing 
a material adjustment to the carrying amounts of assets and liabilities within the next financial year, are those relating to:
  the capitalisation or otherwise of development expenditure;
  the ability of the Group to operate as a “going concern”;
  the carrying value of the Company’s investment in its subsidiaries;
  the future recoverability of goodwill and other intangible assets; and 
  the corresponding review for impairment of those assets.
The Group expends considerable sums on its development projects, with its total research and development costs for 2009 amounting to £5,073,333 
(2008: £6,712,032). The Board has decided not to capitalise any development costs to date as it would not be able to prove reliably that such costs 
could be recovered due to the risk factors involved. Therefore, all such costs have been treated as expenses as they were incurred. Any decision to treat 
part of those costs as capital items could have a significant impact on the Group’s results and balance sheet. 
As explained in note 2.3 above, the accounts are drawn up on the going concern basis which assumes that the Group will be able to access sufficient 
funds to continue to operate for the foreseeable future. If the accounts were to be drawn up on the basis that this assumption was not valid then there 
could be material changes to the carrying values of both assets and liabilities. Silence Therapeutics plc Annual report and accounts 2009
28
Notes to the financial statements continued
year ended 31 December 2009
2. Principal accounting policies continued
2.20 Critical accounting judgements and key sources of estimation uncertainty continued
The Group’s main activities are carried out by subsidiary companies which are financed by ongoing investment by the parent company. These investments are 
carried in the books of the parent company at cost less provisions for impairment. The carrying value at 31 December 2009 is £23,494,482 (2008: £19,917,264). 
The key assumptions concerning the carrying value of the investments in, and loans to, subsidiaries relate to the continuing progress of the research 
and development programmes. As noted below, there are a number of risks and uncertainties around those assumptions and the crystallisation of any 
of those risks could have a significant impact on the assessment of the carrying value of the investment shown in the accounts of the parent company.
Goodwill is carried in the accounts at a value of £8,130,972 at 31 December 2009 (2008: £8,611,087). The movement in the year represents an adjustment 
in respect of fluctuations in foreign exchange rates. 
Other intangible assets have a carrying value at 31 December 2009 of £736,117 (2008: £812,696) and details of the movement in the year, the capitalisation 
and amortisation policy and the basis of the impairment review are set out in note 12.
The key assumptions concerning the carrying value, or otherwise, for both the goodwill and other intangible assets relate to the continuing progress 
of the Group’s research and development programmes, which are subject to risks common to all biotechnology businesses. These risks include the impact 
of competition in the specific areas of development, the potential failure of the projects in development or clinical trials and the possible inability 
to progress projects due to regulatory, manufacturing or intellectual property issues or the lack of available funds or other resources. Furthermore, 
the crystallisation of any of these risks could have a significant impact on the assessment of the value of both goodwill and other intangible assets.
3. Revenue
All revenue in the year was from licence and service fees generated by European operations. The analysis of revenues by geographical destination is:
      2009 2008 
      £ £
Europe     1,601,796 1,113,749
North America     — 1,094,950
Asia/Pacific     121,493 —
      1,723,289 2,208,699
4. Segment reporting
For 2008 and 2009, the Group operated in two specific technology fields, that of RNAi therapeutics and in immunotherapy. These activities were carried 
out in separate operating subsidiaries with certain centralised functions carried out at Group level. These are the three reporting areas used by the Board 
in its management of the entity.
Due to the nature of its licencing activities, the Group’s revenues in any one year often derive from a small number of customers that change year by year. 
During 2009, £763,900 (or 44.3% of Group revenues) arose from a single customer with £275,000 (16.0%) coming from a second customer. During 2008, 
the comparative figures for those two customers were £220,881 (10.0%) and nil, respectively, whilst a different customer provided revenues of £1,094,968 
(representing 49.6% of 2008 Group revenues).
Business segments
    RNAi  Group Consolidated 
    Therapeutics Immunotherapy administration data 
2009   £ £ £ £
Revenue from external customers   1,422,289 301,000 — 1,723,289
Revenue from other operating segments   — — 246,373 —
Operating (loss)/profit   (5,278,476) 205,598 (2,481,537) (7,554,415)
Interest revenue   1,360 773 43,971 46,104
Net (loss)/profit for the year before taxation   (5,277,116) 206,371 (2,437,566) (7,508,311)
Segment assets   10,397,568 161,103 435,631 10,994,302
Segment liabilities   1,525,419 40,670 537,055 2,103,144
Costs to acquire property, plant and equipment   36,648 — — 36,648
Costs to acquire intangible assets   188,494 — — 188,494
Depreciation and amortisation   367,977 2,974 — 370,951
Income tax income   — 37,714 — 37,714
Charge for non‑cash expenses: share‑based payments charge    343,677 — 318,027 661,704 29
Silence Therapeutics plc Annual report and accounts 2009
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4. Segment reporting continued
Business segments continued
    RNAi   Group Consolidated 
    Therapeutics Immunotherapy unallocated data 
2008   £ £ £ £
Revenue from external customers   2,182,699 26,000 — 2,208,699
Revenue from other operating segments   — — 465,318 —
Operating loss   (5,787,779) (271,759) (1,732,099) (7,791,637)
Net finance income   81,817 47,595 227,584 356,996
Net loss for the year before taxation   (5,705,962) (224,164) (1,504,515) (7,434,641)
Segment assets   11,960,517 463,752 1,954,312 14,378,581
Segment liabilities   767,254 46,200 121,147 934,601
Costs to acquire property, plant and equipment   135,584 — — 135,584
Costs to acquire intangible assets   135,752 — — 135,752
Depreciation and amortisation   420,412 2,993 — 423,405
Income tax income   — — — —
Charge for non‑cash expenses: share‑based payments charge    418,805 — 125,353 544,158
The operations, segment assets and liabilities of the RNAi Therapeutics segment are located in Germany. The operations segment assets and liabilities 
of the remaining two segments are located in the United Kingdom.
5. Operating loss 
This is stated after charging:
      2009 2008 
      £ £
Depreciation of property, plant and equipment     150,293 116,489
Amortisation of intangibles     220,658 306,916
Impairment of goodwill     — —
Share‑based payments charge     661,704 544,158
Auditors’ remuneration:
 – audit of parent company     50,340 45,318
 – audit of subsidiary     12,000 10,000
Operating lease payments on offices     295,756 396,628
Fees payable to auditors other than the auditors of the Company amounted to £22,017 (2008: £19,761). Silence Therapeutics plc Annual report and accounts 2009
30
Notes to the financial statements continued
year ended 31 December 2009
6. Directors and staff costs
Staff costs, including Directors’ remuneration, during the year were as follows:
      2009 2008 
      £ £
Wages and salaries     2,561,158 2,867,764
Compensation for loss of office     — 282,296
Social security costs     317,458 364,977
Pension costs     17,500 25,083
      2,896,116 3,540,120
The average number of employees, including both Executive and Non‑executive Directors, during the year was 43 (2008: 51). 
Apart from the Directors, the average number of employees of the parent company was two (2008: two).
Management remuneration paid and other benefits supplied to the Directors during the year was as follows:
      2009 2008 
      £ £
Remuneration     557,200 662,200
Benefits in kind     4,057 4,379
Compensation for loss of office     — 253,667
      561,257 920,246
Charge/(credit) in respect of share‑based payments     204,377 (37,700)
Pension contributions to defined contribution schemes for one Director (2008: one Director)   17,500 17,500
      783,134 900,046
Included in the amounts shown above are payments to third parties amounting to £120,000 for the services of certain Directors (2008: £85,000).
The amounts set out above include remuneration to the highest paid Director as follows: 
      2009 2008 
      £ £
Remuneration     242,000 143,000
Benefits in kind     — 1,173
Compensation for loss of office     — 253,667
Charge in respect of share‑based payments     71,466 —
      313,466 397,840
The Directors of the Group are the same as the key management personnel, as defined by IAS 24 Related Party Transactions.
7. Finance income
The finance income comprises:
      2009 2008 
      £ £
Bank interest receivable     46,104 253,634
Release of provision against loan     — 31,000
Exchange differences     — 72,362
      46,104 356,996 31
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8. Taxation
The credit for the year is made up as follows:
      2009 2008 
      £ £
Corporate taxation on the results for the year: 
– UK     — —
– non‑UK     — —
Research and development tax credit (UK)     — 48,000
Adjustment in respect of prior years (UK)     37,714 (48,000)
Taxation credit for the year     37,714 —
The credit for UK Corporation Tax arises from the Group taking advantage of the legislation regarding the treatment of certain qualifying research 
and development costs. 
A reconciliation of the tax credit appearing in the income statement to the tax credit that would result from applying the standard rate of tax to the results 
for the year is:
      2009 2008 
      £ £
Loss per accounts     (7,508,311) (7,434,641)
Tax credit at the standard rate of Corporation Tax averaged between the two countries of operation  
of 29.6% (2008: 29.8%)     2,219,310 2,215,728
Impact of costs disallowable for tax purposes     (495,490) (163,580)
Impact of income not taxable     41,578 9,239
Deferred tax in respect of temporary differences     181 749
Impact of unrelieved tax losses not provided for     (1,765,579) (2,062,136)
Sub‑total     — —
Relief and refund available in respect of R&D expenditure     — 48,000
Adjustment to that relief in respect of prior periods     37,714 (48,000)
Taxation credit for the year     37,714 —
Estimated tax losses of £46,000,000 (2008: £36,000,000) are available for relief against future profits.
The deferred tax asset not provided for in the accounts based on the estimated tax losses and the treatment of the equity‑settled share‑based payments, 
net of any other temporary differences, is approximately £12,800,000 (2008: £10,200,000).
9. Loss per share
The calculation of the loss per share is based on the loss for the financial year after taxation of £7,470,597 (2008: loss £7,434,641) and on the weighted 
average of 134,640,515 (2008: 119,885,617) ordinary shares in issue during the year. 
The options outstanding at 31 December 2009 and 31 December 2008 are considered to be non‑dilutive in that their conversion into ordinary shares 
would not increase the net loss per share. Consequently, there is no diluted loss per share to report for either year. Silence Therapeutics plc Annual report and accounts 2009
32
Notes to the financial statements continued
year ended 31 December 2009
10. Property, plant and equipment
       Equipment 
       and furniture 
       Total 
Group      £
Cost
At 1 January 2008      3,297,068
Additions      135,584
Disposals      (278,836)
Translation adjustment      932,070
At 31 December 2008      4,085,886
Additions      36,648
Disposals      (181,616)
Translation adjustment      (222,242)
At 31 December 2009      3,718,676
Depreciation
At 1 January 2008      2,898,304
Charge for the year       116,489
Eliminated on disposal      (278,529)
Translation adjustment      813,713
At 31 December 2008      3,549,977
Charge for the year       150,293
Eliminated on disposal      (162,039)
Translation adjustment      (196,231)
At 31 December 2009      3,342,000
Net book value 
As at 31 December 2008      535,909
As at 31 December 2009      376,676
11. Goodwill
The carrying amount of goodwill is wholly attributable to the acquisition of Silence Therapeutics AG in 2005.
      2009 2008 
      £ £
Balance at start of year     8,611,087 6,653,990
Translation adjustment     (480,115) 1,957,097
Balance at end of year     8,130,972 8,611,087
In accordance with IAS 36 Impairment of Assets, the carrying value of goodwill has been assessed comparing its carrying value to its recoverable amount. 
The recoverable amount has been calculated by the Directors as being the fair value less costs of sale. 
To arrive at fair value less costs of sale, the Directors have reviewed observable market information, that being the price to sales ratios of recent 
transactions in the sector as well as enterprise value/turnover ratios based on recent deals and similar quoted companies. 
The value of Silence Therapeutics AG is largely influenced by the expected success of its RNAi technology which has been successful in preliminary trials 
to date. The Directors are of the opinion that this supports the fair value less costs to sale approach to assessing the carrying value of Silence Therapeutics AG 
and consider this to be a more relevant and reliable methodology, in this instance, than value in use. 
On the basis of these assessments, the Board considers there is no need to impair the carrying value of goodwill.  33
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12. Other intangible assets
      Internally  
      generated  
      patents   
      and patent   
     Licences applications Total 
     £ £ £
Cost
At 1 January 2008    2,026,796 567,883 2,594,679
Additions    10,429 125,323 135,752
Translation adjustment    597,663 185,459 783,122
At 31 December 2008    2,634,888 878,665 3,513,553
Additions    416 188,078 188,494
Translation adjustment    (146,921) (54,233) (201,154)
At 31 December 2009    2,488,383 1,012,510 3,500,893
Amortisation
At 1 January 2008    1,693,050 121,926 1,814,976
Charge for the year     230,070 76,846 306,916
Translation adjustment    531,802 47,163 578,965
At 31 December 2008    2,454,922 245,935 2,700,857
Charge for the year     100,433 120,225 220,658
Translation adjustment    (139,675) (17,064) (156,739)
At 31 December 2009    2,415,680 349,096 2,764,776
Net book value 
As at 31 December 2008    179,966 632,730 812,696
As at 31 December 2009    72,703 663,414 736,117
The licences included above have finite useful lives estimated to be of ten years from date of initial acquisition, over which period the assets are amortised. 
The Group’s internally generated patent costs above represent expenses connected with filings for patent registration in respect of technology that has been 
developed by the Group for use in revenue generating activities. These costs are amortised on a straight‑line basis over ten years, commencing upon 
the completion of the relevant asset. The charge for amortisation is included within research and development costs in the income statement. 
The Group tests for possible impairment of definite‑lived intangible assets on a regular basis. If indicators of possible impairment exist, such as a change 
of use of the asset, a reduction in operating cash flow or a change in technology, the Company compares the discounted cash flows related to the asset 
to the carrying value of the asset. If the carrying value is greater than the discounted cash flow amount, an impairment charge is recorded for the amount 
necessary to reduce the carrying value of the asset to fair value. Fair value for the purpose of the impairment tests is determined based on current market 
value or discounted future cash flows. In determining the fair value, certain assumptions are made concerning, for example, estimated cash flow and growth 
of the Group’s operations.
13. Investments
      2009 2008 
Company     £ £
Investment in subsidiary undertakings     23,494,482 19,917,264 Silence Therapeutics plc Annual report and accounts 2009
34
Notes to the financial statements continued
year ended 31 December 2009
13. Investments continued
The investment in subsidiary undertakings is made up as follows:
     Investment Impairment Net 
     at cost provision total 
     £ £ £
Shares in subsidiary undertakings
At 1 January 2008    12,719,169 (209,991) 12,509,178
Additions    6,724,938 — 6,724,938
At 31 December 2008    19,444,107 (209,991) 19,234,116
Additions    3,746,635 4,514 3,751,149
At 31 December 2009    23,190,742 (205,477) 22,985,265
Loans to subsidiary undertakings
At 1 January 2008    23,265,772 (22,095,476) 1,170,296
Additions    109,384 (596,532) (487,148)
At 31 December 2008    23,375,156 (22,692,008) 683,148
Reductions    (310,084) (136,153) (173,931)
At 31 December 2009    23,065,072 (22,555,855) 509,217
Total investment 
As at 31 December 2008    42,819,263 (22,901,999) 19,917,264
As at 31 December 2009    46,255,814 (22,761,332) 23,494,482
Subsidiary companies
The principal activity of all subsidiaries is the research and development of pharmaceutical products: 
    Place of  Proportion of 
    incorporation Principal ownership 
Name   and operation technology area interest
Silence Therapeutics AG   Germany RNAi therapeutics 100%
Stanford Rook Ltd   England Immunotherapy 100%
Innopeg Ltd   England Not active 100%
The Company has made additional investment during the year in its operating subsidiary Silence Therapeutics AG. Silence Therapeutics plc has made 
an impairment provision against the investment and loans to Stanford Rook Limited and Innopeg Limited to the extent that they are deemed to be not recoverable. 
No impairment provision has been made against the investment in Silence Therapeutics AG as the Directors believe that the fair value exceeds the cost 
of investment to date. 
14. Trade and other receivables
    Group Company Group Company 
    2009 2009 2008 2008 
    £ £ £ £
Trade receivables   164,871 — 692,009 —
Other receivables   197,212 78,818 96,362 65,747
Prepayments   198,107 12,418 210,331 —
    560,190 91,236 998,702 65,747
The Directors consider that the carrying amount of trade and other receivables approximates to their fair value. Fair values have been calculated by discounting 
cash flows at prevailing interest rates. See also note 24.
No interest is charged on outstanding trade receivables. 35
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15. Cash and cash equivalents
    Group Company Group Company 
    2009 2009 2008 2008 
    £ £ £ £
Cash at bank   1,131,146 358,256 3,350,187 1,914,188
Cash at bank comprises of balances held by the Group in current and short‑term bank deposits with a maturity of three months or less. The carrying amount 
of these assets approximates to their fair value. The deposits held at bank are treated as cash equivalents under the definitions of IAS 7 “Cash Flow Statements”. 
Although the sums are held on short‑term fixed rate deposit, they are instantly available to the Group but only by breaking the terms of the deposit which 
may incur minor penalties. During the year, the effective rates of interest on fixed rate deposits ranged between 0.79% and 3.98% per annum.
16. Trade and other payables 
    Group Company Group Company 
    2009 2009 2008 2008 
    £ £ £ £
Trade payables   626,315 522,500 432,887 55,512
Social security and other taxes   24,149 24,149 23,225 —
Deferred revenues   511,766 — 95,635 —
Accruals and other payables   940,914 625,192 382,854 65,635
Amounts due to Group companies   — 13,864 — 25,627
    2,103,144 1,185,705 934,601 146,774
Trade payables and accruals principally comprise amounts outstanding for trade purchases and continuing costs. The Directors consider that the carrying 
amount of trade and other payables approximates to their fair value. Fair values have been calculated by discounting cash flows at prevailing interest rates. 
See also note 24.
17. Deferred taxation
The following are the major deferred tax liabilities and assets recognised by the Group:
      2009 2008 
      £ £
Deferred tax liability: 
– in respect of intangible assets     214,000 228,000
Liability     214,000 228,000
Less: offset of deferred tax asset below     (214,000) (228,000)
      — —
      2009 2008 
      £ £
Deferred tax asset:
– in respect of available tax losses     11,900,000 10,200,000
– in respect of share‑based payments     890,000 812,000
Deferred tax asset     12,790,000 11,012,000
Less: offset against deferred tax liability     (214,000) (228,000)
 provision against asset      (12,576,000) (10,784,000)
Asset     — — Silence Therapeutics plc Annual report and accounts 2009
36
Notes to the financial statements continued
year ended 31 December 2009
18. Share capital
      2009 2008 
      £ £
Allotted called up and fully paid 
135,033,392 (2008: 119,913,392) ordinary shares     1,350,334 1,199,134
The Group has only one class of share. All ordinary shares have equal voting rights and rank pari passu for the distribution of dividends and repayment 
of capital.
Details of the shares issued by the Company during the current and previous years are as follows:
      2009 2008 
      £ £
Number of shares in issue at 1 January 2008      119,883,536
Shares issued during 2008:
– upon the exercise of staff share options at 12.75p per share      29,856
Number of shares in issue at 31 December 2008      119,913,392
Shares issued during 2009:
– issue of shares for cash at 18p per share     15,000,000
– upon the exercise of staff share options at 12.75p per share     100,000
– upon the exercise of staff share options at 19p per share     20,000
Total issued in year      15,120,000
Number of shares in issue at 31 December 2009      135,033,392
The Group operates both an Inland Revenue Approved Share Option Scheme and an Unapproved Share Option Scheme. All Directors and UK employees 
are eligible for both schemes. The Group has also granted options to certain Directors and employees under the auspices of an Enterprise Management 
Incentive Scheme. 
At 31 December 2009 there were options outstanding over 20,585,547 (2008: 22,058,911) unissued ordinary shares and warrants outstanding over 
925,926 unissued ordinary shares. 
Details of the options outstanding are as follows:
       Exercise price 
Exercise date     Number  P
At any time up to 27 May 2014     900,000 27.0p
At any time up to 24 July 2015     8,600,000 23.0p
At any time up to 25 July 2016     755,548 12.75p
At any time up to 23 November 2016     1,200,000 43.0p
At any time up to 29 May 2017     70,000 109p
Between 31 March 2010 and 29 May 2017     10,000 109p
At any time up to 26 July 2017     668,000 127p
Between 26 July 2010 and 26 July 2017     332,000 127p
At any time up to 14 December 2017     386,669 67.75p
Between 14 December 2010 and 14 December 2017     193,331 67.75p
At any time up to 16 May 2018     26,667 41.5p
Between 7 May 2010 and 6 May 2018     26,667 41.5p
Between 7 May 2011 and 6 May 2018     51,666 41.5p
At any time up to 25 September 2018     405,000 29.5p
Between 26 September 2010 and 25 September 2018     5,000 29.5p
Between 26 September 2011 and 25 September 2018     5,000 29.5p
At any time up to 4 December 2018     1,916,669 20p
Between 5 December 2010 and 4 December 2018     2,716,682 20p
Between 5 December 2011 and 4 December 2018     2,316,648 20p
Total     20,585,547 37
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18. Share capital continued
The options held by the Directors at the beginning and end of the year are as detailed below. No Director was granted or exercised options during 2009.
  At 1 January Lapsed in At 31 December Exercise price Earliest date Latest date 
Director 2009 the year 2009 P of exercise of exercise
I G Ross
– Unapproved Scheme 500,000 — 500,000 27p 28/05/04 27/05/14
– Unapproved Scheme 1,000,000 — 1,000,000 23p 25/07/05 24/07/15
– Unapproved Scheme 1,000,000 — 1,000,000 23p 25/07/06 24/07/15
– Unapproved Scheme 1,000,000 — 1,000,000 23p 25/07/07 24/07/15
– Unapproved Scheme 1,000,000 — 1,000,000 23p 25/07/08 24/07/15
– Unapproved Scheme 150,000 — 150,000 43p 24/11/07 23/11/16
– Unapproved Scheme 125,000 — 125,000 43p 24/11/08 23/11/16
– Unapproved Scheme 125,000 — 125,000 43p 24/11/09 23/11/16
– Unapproved Scheme 1,100,000 — 1,100,000 20p 05/12/09 04/12/18
J M Davies
– EMI Scheme 200,000 — 200,000 27p 28/05/07 28/05/14
– Unapproved Scheme 250,000 — 250,000 23p 25/07/05 24/07/15
– Unapproved Scheme 300,000 — 300,000 23p 25/07/06 24/07/15
– Unapproved Scheme 350,000 — 350,000 23p 25/07/07 24/07/15
– Unapproved Scheme 400,000 — 400,000 23p 25/07/08 24/07/15
– Unapproved Scheme 75,000 — 75,000 43p 24/11/07 23/11/16
– Unapproved Scheme 62,500 — 62,500 43p 24/11/08 23/11/16
– Unapproved Scheme 62,500 — 62,500 43p 24/11/09 23/11/16
– Unapproved Scheme 750,000 — 750,000 20p 05/12/09 04/12/18
J L Curnock Cook
– Unapproved Scheme 50,000 — 50,000 23p 25/07/05 24/07/15
– Unapproved Scheme 60,000 — 60,000 23p 25/07/06 24/07/15
– Unapproved Scheme 70,000 — 70,000 23p 25/07/07 24/07/15
– Unapproved Scheme 70,000 — 70,000 23p 25/07/08 24/07/15
– Unapproved Scheme 200,000 (200,000) — 75p 30/09/07 30/09/09
– Unapproved Scheme 350,000 — 350,000 20p 05/12/09 04/12/18
H R P Reynolds
– Unapproved Scheme 200,000 — 200,000 27p 28/05/04 27/05/14
– Unapproved Scheme 50,000 — 50,000 23p 25/07/05 24/07/15
– Unapproved Scheme 60,000 — 60,000 23p 25/07/06 24/07/15
– Unapproved Scheme 70,000 — 70,000 23p 25/07/07 24/07/15
– Unapproved Scheme 70,000 — 70,000 23p 25/07/08 24/07/15
– Unapproved Scheme 200,000 (200,000) — 75p 30/09/07 30/09/09
– Unapproved Scheme 350,000 — 350,000 20p 05/12/09 04/12/18
D C U’Prichard
– Unapproved Scheme 50,000 — 50,000 23p 25/07/05 24/07/15
– Unapproved Scheme 60,000 — 60,000 23p 25/07/06 24/07/15
– Unapproved Scheme 70,000 — 70,000 23p 25/07/07 24/07/15
– Unapproved Scheme 70,000 — 70,000 23p 25/07/08 24/07/15
– Unapproved Scheme 200,000 (200,000) — 75p 30/09/07 30/09/09
– Unapproved Scheme 350,000 — 350,000 20p 05/12/09 04/12/18 Silence Therapeutics plc Annual report and accounts 2009
38
Notes to the financial statements continued
year ended 31 December 2009
18. Share capital continued
  At 1 January Lapsed in At 31 December Exercise price Earliest date Latest date 
Director 2009 the year 2009 P of exercise of exercise
B O Wetzel
– Unapproved Scheme 50,000 — 50,000 23p 25/07/05 24/07/15
– Unapproved Scheme 60,000 — 60,000 23p 25/07/06 24/07/15
– Unapproved Scheme 70,000 — 70,000 23p 25/07/07 24/07/15
– Unapproved Scheme 70,000 — 70,000 23p 25/07/08 24/07/15
– Unapproved Scheme 200,000 (200,000) — 75p 30/09/07 30/09/09
– Unapproved Scheme 350,000 — 350,000 20p 05/12/09 04/12/18
A Clancy
– Unapproved Scheme 200,000 — 200,000 29.5p 26/09/08 25/09/18
J A P Randall
– Unapproved Scheme 200,000 — 200,000 29.5p 26/09/08 25/09/18
Sub‑total 12,250,000 (800,000) 11,450,000
None of the options granted under any of the schemes have any future performance or qualifying conditions attached to them, other than remaining 
as an employee. The Remuneration Committee did not believe that the inclusion of such conditions for staff or Directors was appropriate at the time 
of granting these options.
The market price of the shares at the year end was 18.5p per share (31 December 2008: 18p). 
During the year, the minimum and maximum prices were 18p and 33p per share respectively.
At both 31 December 2009 and 31 December 2008, the Group had outstanding warrants over 925,926 shares that are convertible at 27p per share. 
All warrants may be exercised at any time up to 24 July 2010.
19. Capital reserves
    Share  Share‑based  
    premium Merger payment  
    account reserve reserve Total 
Group   £ £ £ £
At 1 January 2008   37,964,447 6,140,874 2,359,844 46,465,165
On options exercised during the year   3,509 — (1,687) 1,822
On vested options lapsed during the year    — — (731) (731)
On options issued during the year   — — 544,158 544,158
Movement in the year   3,509 — 541,740 545,249
At 31 December 2008   37,967,956 6,140,874 2,901,584 47,010,414
On shares issued in the year   2,550,000 — — 2,550,000
 – less costs of share issue   (50,000) — — (50,000)
On options in issue during the year   — — 661,704 661,704
On options exercised during the year   15,350 — (4,514) 10,836
On vested options lapsed during the year    — — (372,883) (372,883)
Movement in the year   2,515,350 — 284,307 2,799,657
At 31 December 2009   40,483,306 6,140,874 3,185,891 49,810,071 39
Silence Therapeutics plc Annual report and accounts 2009
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19. Capital reserves continued
    Share  Share‑based  
    premium Merger payment  
    account reserve reserve Total 
Company   £ £ £ £
At 1 January 2008   37,964,447 5,956,958 2,359,844 46,281,249
On options exercised during the year   3,509 — (1,687) 1,822
On vested options lapsed during the year    — — (731) (731)
On options issued during the year   — — 544,158 544,158
Movement in the year   3,509 — 541,740 545,249
At 31 December 2008   37,967,956 5,956,958 2,901,584 46,826,498
On shares issued in the year   2,550,000 — — 2,550,000
– less costs of share issue   (50,000) — — (50,000)
On options in issue during the year   — — 661,704 661,704
On options exercised during the year   15,350 — (4,514) 10,836
On vested options lapsed in the year    — — (372,883) (372,883)
Movement in the year   2,515,350 — 284,307 2,799,657
At 31 December 2009   40,483,306 5,956,958 3,185,891 49,626,155
Due to the size of the retained loss, the Company has no distributable reserves.
20. Equity‑settled share‑based payments
The Company has two share option schemes open to all employees of the Group. Options are exercisable at a price equal to the market price of the Company’s 
shares on the date of grant. 
In the Inland Revenue Approved Scheme the vesting period is three years and should the options remain unexercised they lapse after ten years from 
the date of grant. The options also lapse after six months following the employee leaving the Group. 
Under the Unapproved Share Option Scheme, the options vest at dates set by the Board at the time the option is granted. The options lapse after 
three months following the employee leaving the Group. 
As part of the fee structure in respect of the acquisition of Silence Therapeutics AG and the subsequent fundraising in mid‑2005, the Group issued warrants 
to its advisers which could be exercised at any time within five years from the date of issue. Most of those warrants have been converted into shares, 
see note 19 above. The holders may convert the remaining warrants into a maximum of 925,926 ordinary shares at a price of 27p per share. 
Details of the share options and warrants outstanding at the year end are as follows:
  2009  2008
     Weighted average   Weighted average 
     exercise price   exercise price 
    Number P Number   P
Options
Outstanding at the beginning of the year   22,058,911 31.69p 17,601,728 47.18p
Granted during the year   — — 7,559,999 20.98p
Lapsed during the year   1,353,364 61.67p 3,072,960 94.23p
Exercised during the year   120,000 13.79p 29,856 12.75p
Outstanding at the year end   20,585,547 29.82p 22,058,911 31.69p
Exercisable at the year end   14,928,553 30.37p 4,231,229 31.36p
Warrants
Outstanding at the beginning of the year   925,926 27.00p 925,926 27.00p
Granted during the year   — — — —
Lapsed during the year   — — — —
Exercised during the year   — — — —
Outstanding at the year end   925,926 27.00p 925,926 27.00p
Exercisable at the year end   925,926 27.00p 925,926 27.00p Silence Therapeutics plc Annual report and accounts 2009
40
Notes to the financial statements continued
year ended 31 December 2009
20. Equity‑settled share‑based payments continued
The weighted average share prices at each date when share options were exercised during the year were:
       Weighted average 
       share price  
Date option exercised      P
14 July 2009      24p
The options outstanding at the year end have a weighted average remaining contractual life of 7.0 years (2008: 7.7 years). The exercise price of the 
options outstanding at the year end range from 12.75p to 127p per share. Full details are given in note 18 above.
The Group granted no options during the year. In previous years the fair values of options granted were calculated using a Binomial model, and the inputs 
into the model were as follows:
      2008 2007
Weighted average share price     30.509p 88.596p
Weighted average exercise price     20.981p 94.989p
Expected volatility     85–115% 72–78%
Risk free rate     3.05–4.48% 4.56–5.52%
Expected dividend yield     — —
Expected volatility was determined using as a base the share price movements recorded over the previous four years and taking into account any specific 
factors impacting during that period.
The expected life used in the model has been adjusted, based on management’s best estimate for the effects of non‑transferability, exercise restrictions 
and behavioural considerations. 
The Group recognised total charges of £661,704 (2008: £544,158) related to equity‑settled share‑based payment transactions during the year.
21.  Capital commitments
There were no capital commitments at 31 December 2009 or 31 December 2008.
22. Contingent liabilities
There were no contingent liabilities at 31 December 2009 or at 31 December 2008.
23. Commitments under operating leases
There were no commitments under operating leases at 31 December 2009 or at 31 December 2008.
24. Financial instruments and risk management
The Group’s financial instruments comprise primarily cash and various items such as trade debtors and trade creditors which arise directly from its operations. 
The main purpose of these financial instruments is to provide working capital for the Group’s operations. The Group does not utilise complex financial 
instruments or hedging mechanisms in respect of its non‑Sterling operations. 
Financial assets by category
The categories of financial assets (as defined by International Accounting Standard 39: Financial Instruments: Recognition and Measurement – IAS 39) 
included in the balance sheet and the heading in which they are included are as follows:
    Group Company Group Company 
    2009 2009 2008 2008 
    £ £ £ £
Current assets
Trade and other receivables   362,083 78,814 788,371 65,747
Cash and cash equivalents   1,131,146 358,256 3,350,187 1,914,188
Categorised as loans and receivables   1,493,229 437,070 4,138,558 1,979,935
All amounts are short term and none are past due at the reporting date.  41
Silence Therapeutics plc Annual report and accounts 2009
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24. Financial instruments and risk management continued
Financial liabilities by category
The categories of financial liabilities (as defined by IAS 39) included in the balance sheet and the heading in which they are included are as follows:
    Group Company Group Company 
    2009 2009 2008 2008 
    £ £ £ £
Current liabilities
Trade and other payables   1,567,229 1,161,556 815,741 146,774
Categorised as financial liabilities measured at amortised cost   1,567,229 1,161,556 815,741 146,774
All amounts are short term and payable in zero to three months. 
Credit risk
The maximum exposure to credit risk at the reporting date by class of financial asset was:
    Group Company Group Company 
    2009 2009 2008 2008 
    £ £ £ £
Loans and receivables   1,750,534 449,492 4,418,889 1,979,935
Interest rate risk
The nature of the Group’s activities and the basis of funding are such that the Group has significant liquid resources. The Group uses these resources 
to meet the cost of future research and development activities. Consequently, it seeks to minimise risk in the holding of its bank deposits while maintaining 
a reasonable rate of interest. The Group is not financially dependent on the income earned on these resources and therefore the risk of interest rate fluctuations 
is not significant to the business. Nonetheless, the Directors take steps to secure rates of interest which generate a return for the Group by depositing sums 
which are not required to meet the immediate needs of the Group in interest‑bearing deposits. Other balances are held in interest‑bearing, instant access 
accounts. All deposits are placed with main clearing banks to restrict both credit risk and liquidity risk. The deposits are placed for the short term, between 
one and three months, to provide flexibility and access to the funds and to avoid locking into potentially unattractive interest rates. 
Liquidity risk
The Group’s liquid resources are invested having regard to the timing of payments to be made in the ordinary course of the Group’s activities. All financial 
liabilities are payable in the short term (between zero and three months) and the Group maintains adequate bank balances in either instant access or short 
term deposits to meet those liabilities as they fall due.
Currency risk
The Group operates in a global market with income possibly arising in a number of different currencies, principally in Sterling, US Dollars or Euros. The majority 
of the operating costs are incurred in Euros with the rest predominantly in Sterling. The Group does not hedge potential future income since the existence, 
quantum and timing of such income cannot be accurately predicted.
Financial assets and liabilities denominated in Euros and translated into Sterling at the closing rate were:
    Group Company Group Company 
    2009 2009 2008 2008 
    £ £ £ £
Financial assets   1,141,216 — 1,979,450 —
Financial liabilities   (890,633) — (767,255) —
Net financial assets   250,583 — 1,212,195 —
The following table illustrates the sensitivity of the net result for the year and the reported financial assets of the Group in regards to the exchange rate 
for Sterling:Euro.
For a number of years until 2007 the Sterling:Euro exchange rate operated within a relatively close trading range. However, there was a sharp fall in Sterling 
towards the end of 2007, which continued through 2008 before stabilising to a degree during 2009. Nonetheless, that movement has resulted in the exchange 
rate being approximately 30% different from the 2007 rate. The table shows the impact of a further fall or strengthening of Sterling against the Euro by 20%.
     2009 If Sterling If Sterling 
     As reported  rose 20% fell 20% 
     £ £ £
Group result for the year    (7,470,597) (6,590,822) (8,790,170)
Euro denominated net financial assets    250,583 208,819 313,228
Total equity at 31 December 2009    8,891,155 7,393,458 12,278,715 Silence Therapeutics plc Annual report and accounts 2009
42
Notes to the financial statements continued
year ended 31 December 2009
24. Financial instruments and risk management continued
Currency risk continued
     2008 If Sterling If Sterling 
     As reported  rose 20% fell 20% 
     £ £ £
Group result for the year    (7,434,641) (6,977,089) (7,979,591)
Euro denominated net financial assets    1,212,195 1,010,163 1,515,244
Total equity at 31 December 2008    13,443,979 11,644,059 16,143,859
25. Related party transactions
During the year the Company charged a management fee to its subsidiary companies Stanford Rook Limited amounting to £15,251 (2008: £62,830) 
and Silence Therapeutics AG amounting to £231,123 (2008: £402,488). Both amounts were added to the cost of the Company’s investment in these 
two subsidiaries. In addition, Stanford Rook Limited settled expenses on behalf of the Company amounting to £541,205 (2008: £491,673), which has 
been deducted from the Company’s cost of investment in this subsidiary.
26. Post balance sheet event
26.1 Acquisition of Intradigm
On 5 January 2010, the Company acquired the entire issued share capital of Intradigm Corporation, a company also engaged in the development 
of RNAi‑based therapeutics, by issuance of 79,640,668 ordinary shares representing consideration of £18,317,354. The fair value of each share was 
23p, based on the price at which the Company issued shares in a fundraising completed at the same time. Additional consideration for the acquisition 
included 2.7m shares and 1.14m immediately vesting options, which were issued to executives of Intradigm on completion of the deal.
The total cost of acquisition includes the components stated below:
       £’000
Purchase price settled in shares      18,317
Value of shares issued to Intradigm executives      621
Value of options issued to Intradigm executives      108
Total cost of acquisition      19,046
The carrying amount and fair value of the assets and liabilities acquired are as follows:
      Carrying amount Fair value 
      £’000 £’000
Property, plant and equipment     266 266
Trade and other receivable     114 114
Cash and short term deposits     801 801
Trade and other payables     (1,698) (1,698)
Short‑term borrowings     (1,876) (1,876)
Deferred revenue     (423) (423)
Fair value of net liabilities acquired     (2,816) (2,816)
Goodwill arising on acquisition     21,862 21,862
      19,046 19,046
The carrying value of goodwill arising on acquisition reflects the position Intradigm occupies in the high profile field of RNAi therapeutics and the synergies 
expected to arise from combination with the Company, already a leader in the field. Due to the early stage nature of the projects, the timing of future cash flows is 
uncertain and so a value in use calculation is not possible. None of the goodwill is expected to be deductible for income tax purposes. Management have 
yet to complete their assessment of any identifiable intangible assets and the disclosed figures are therefore provisional and may be subject to change.
26.2 Issue of shares in conjunction with the Intradigm acquisition
On 5 January 2010, the Company issued 65,217,392 new ordinary shares of 1p each at a price of 23p per share for a total cash consideration of £15m 
before expenses of the issue. The nominal value of these shares was £652,173. 43
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
Company information and advisers
Secretary
Max Herrmann
Registered office
22 Melton Street 
London NW1 2BW
Registered number 
2992058
Nominated advisers
Nomura Code Securities Ltd
1 Carey Lane 
London EC2V 8AE
Registrars
Capita IRG plc
Northern House 
Woodsome Park 
Fenay Bridge 
Huddersfield HD8 0LA
Auditor
Grant Thornton UK LLP
Grant Thornton House 
Melton Street 
Euston Square 
London NW1 2EP Silence Therapeutics plc Annual report and accounts 2009
44
Notice of Annual General Meeting
THIS DOCUMENT IS IMPORTANT AND REQUIRES YOUR IMMEDIATE ATTENTION.  If you are in any doubt as to what action to take, 
you should consult your stockbroker, solicitor, accountant or other appropriate independent professional adviser authorised under 
the Financial Services and Markets Act 2000.  If you have sold or otherwise transferred all your shares in Silence Therapeutics plc, 
please forward this document and the accompanying form of proxy to the person through whom the sale or transfer was effected, 
for transmission to the purchaser or transferee.
Notice is hereby given that the annual general meeting (“Annual General Meeting”) of Silence Therapeutics plc (the “Company”) will be held at the 
Royal Institution, 21 Albemarle Street, London W1S 4BS at 10.00am on Friday 18 June 2010 to consider, and if thought fit, to pass the following 
resolutions. It is intended to propose resolution 8 as a special resolution. All other resolutions will be proposed as ordinary resolutions.
Ordinary business
1. To receive the accounts for the financial year ended 31 December 2009, together with the reports of the directors and auditors thereon.
2.  To reappoint Grant Thornton UK LLP as auditors of the Company for the financial year ending 31 December 2010 and to authorise the directors 
to fix their remuneration.
3. That Philip Haworth, who has been appointed since the last Annual General Meeting, be re‑elected as a director of the Company.
4. That Max Herrmann, who has been appointed since the last Annual General Meeting, be re‑elected as a director of the Company.
5. That David Mack, who has been appointed since the last Annual General Meeting, be re‑elected as a director of the Company.
6. That Jamie Topper, who has been appointed since the last Annual General Meeting, be re‑elected as a director of the Company.
7.  That the Directors be and they are hereby generally and unconditionally authorised for the purposes of Section 551 of the Companies Act 2006 
(the “Act”) to exercise all the powers of the Company to allot shares and grant rights to subscribe for, or convert any security into, shares up to an 
aggregate nominal amount (within the meaning of Section 551(3) and (6) of the Act) of £279,891 (being 10% of the Company’s issued share capital 
as at 26 May 2010) provided that this authority shall expire on whichever is the earlier of the conclusion of the next Annual General Meeting of the 
Company or the date falling fifteen months from the date of passing of this resolution (save that the Company may, before such expiry, make any offer 
or agreement which would, or might, require shares to be allotted or rights to be granted after such expiry and the directors may allot shares, or grant 
rights to subscribe for or to convert any security into shares, in pursuance of any such offer or agreement as if the authority conferred hereby had not 
expired). This authority is in substitution for any and all authorities previously conferred on the Directors for the purposes of Section 551 of the Act.
Special business
8.  That the directors be and they are hereby empowered pursuant to Section 570(1) of the Act, subject to the passing of resolution 7 above, to allot 
equity securities (as defined in Section 560(1) of the Act) of the Company for cash pursuant to the authority conferred on them by resolution 7 above 
as if Section 561 of the Act did not apply to any such allotment provided that such power shall be limited to the allotment of equity securities for cash: 
 8.1  in connection with or pursuant to a rights issue or open offer or any other pre‑emptive offer in favour of the holders of equity securities where the 
equity securities respectively attributable to the interests of all such holders are proportionate (as nearly as practicable) to the respective amounts 
of equity securities held by them subject to such exclusions or other arrangements as the directors may consider necessary or appropriate to deal 
with the requirements of any regulatory body or stock exchange in any territory, fractional entitlements, treasury shares, record dates or legal or 
practical problems arising in, or pursuant to, the laws of any territory; and
 8.2  (other than pursuant to sub‑paragraph 8.1 above) up to an aggregate nominal amount of £279,891, and the power hereby conferred shall operate 
in substitution for any and all previous power given to the directors pursuant to Section 570(1) of the Act and shall expire on whichever is the 
earlier of the conclusion of the next Annual General Meeting of the Company or the date falling fifteen months from the date of passing of this 
resolution (save that the Company may, before such expiry make any offer or agreement which would, or might, require equity securities to be 
allotted after such expiry and the Directors may allot equity securities in pursuance of such offer or agreement as if the power hereby conferred 
had not expired). 
  Your Board believes that the resolutions to be proposed at the Annual General Meeting are in the best interests of the Company and its shareholders 
as a whole. Accordingly the Directors unanimously recommend that the shareholders vote in favour of the resolutions, as they intend to do in respect 
of their own beneficial holdings of shares in the Company.
By order of the Board
Max Herrmann Registered office
Company Secretary 22 Melton Street
26 May 2010 London NW1 2BW 45
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
Explanatory notes to the notice of Annual 
General Meeting
Proxies
1. A Form of Proxy is enclosed for your use.
2.  A member of the Company entitled to attend and vote at the meeting may appoint one or more proxies to exercise all or any of his rights to attend, 
to speak and to vote on his/her behalf. A proxy need not be a member of the Company. A member may appoint more than one proxy in relation to the 
meeting, provided that each proxy is appointed to exercise the rights attached to a different share or shares held by him, (you may photocopy this 
form). The instrument appointing a proxy and the power of attorney or other authority (if any) under which it is signed or a notarially certified copy 
of that power or other authority (if any), must be deposited with the Company’s registrars, Capita Registrars, PXS, The Registry, 34 Beckenham Road, 
Kent BR3 4TU not less than 48 hours before the time of the meeting, or any adjournment thereof. If you are a CREST member, see note 5 below.
3.  Completion of a Form of Proxy or any CREST Proxy Instruction will not preclude a member from attending and voting in person at the meeting should 
he/she wish to do so.
4.  Pursuant to Regulation 41 of the Uncertificated Securities Regulations 2001, the Company specifies that only those shareholders registered in 
the register of members of the Company as at 6.00pm on Wednesday 16 June 2010 or, in the event that this meeting is adjourned, in the register of 
members of the Company at 6.00pm on the day two days prior to the adjourned meeting, shall be entitled to attend and vote at the Annual General 
Meeting in respect of the number of shares registered in their name at the time. Subsequent changes to entries on the relevant register of securities 
will be disregarded in determining the rights of any person to attend or vote at the meeting.
5.  CREST members who wish to appoint a proxy or proxies through the CREST electronic proxy appointment service may do so for the Annual General 
Meeting to be held on 18 June 2010 at 10.00am and any adjournment(s) thereof by using the procedures described in the CREST Manual. CREST 
personal members or other CREST sponsored members, and those CREST members who have appointed a voting service provider should refer to 
their CREST sponsors or voting service provider(s), who will be able to take the appropriate action on their behalf. 
  In order for a proxy appointment or instruction made by means of CREST to be valid, the appropriate CREST message (a “CREST Proxy Instruction”) 
must be properly authenticated in accordance with Euroclear UK & Ireland Limited’s specifications and must contain the information required for 
such instructions, as described in the CREST Manual available via (www.euroclear.com/CREST). The message, regardless of whether it constitutes 
the appointment of a proxy or an amendment to the instruction given to a previously appointed proxy, must be transmitted so as to be received by the 
Company’s agent, Capita Registrars Limited (CREST Participant ID: RA10), no later than 48 hours before the time appointed for the meeting. For this 
purpose, the time of receipt will be taken to be the time (as determined by the time stamp applied to the message by the CREST Application Host) 
from which the Company’s agent is able to retrieve the message by enquiry to CREST in the manner prescribed by CREST. After this time any change 
of instructions to proxies appointed through CREST should be communicated to the appointee through other means.
  CREST members and, where applicable, their CREST sponsor or voting service provider should note that Euroclear UK & Ireland Limited does not 
make available special procedures in CREST for any particular messages. Normal system timings and limitations will therefore apply in relation to the 
input of CREST Proxy Instructions. It is the responsibility of the CREST member concerned to take (or, if the CREST member is a CREST personal 
member or sponsored member or has appointed a voting service provider, to procure that his CREST sponsor or voting service provider takes) such 
action as shall be necessary to ensure that a message is transmitted by means of the CREST system by any particular time. In this connection, 
CREST members and, where applicable, their CREST sponsor or voting service provider are referred in particular to those sections of the CREST 
Manual concerning practical limitations of the CREST system and timings.
  The Company may treat as invalid a CREST Proxy Instruction in the circumstances set out in Regulation 35(5)(a) of the Uncertificated Securities 
Regulations 2001.
6.  Any corporation which is a member can appoint one or more corporate representatives who may exercise on its behalf all of its powers as a member 
provided that they do not do so in relation to the same shares.
Documents on display
7.  Copies of the Directors’ service contracts and letters of engagement will be available for inspection at the registered office of the Company during 
the usual business hours on any weekday (Saturday, Sunday and public holidays excepted) from the date of this notice up to and including the date 
of the meeting and at the place of the meeting for 15 minutes prior to and during the meeting.
Total number of shares and voting rights
8.  As at 26 May 2010 (being the last practicable day prior to the publication of this notice) the Company’s issued share capital consists of 279,891,452 
ordinary shares, carrying one vote each. Therefore, the total voting rights in the Company as at that date are 279,891,452.
Communication
9.  You may not use any electronic address (within the meaning of Section 333(4) of the Companies Act 2006) provided in this Notice of Meeting 
(or in any related documents including the proxy form) to communicate with the Company for any purposes other than those expressly stated. Silence Therapeutics plc Annual report and accounts 2009
46
Explanatory notes to certain of the Resolutions
10  For the benefit of shareholders we provide the following notes concerning some of the resolutions to be placed before them at the Annual General Meeting. 
(a) Resolutions 3, 4, 5 and 6. 
 Dr Phil Haworth
 Chief Executive Officer
  Dr Haworth was appointed Chief Executive Officer of Silence Therapeutics in January 2010 following the Company’s merger with Intradigm 
Corporation. Prior to this role, Dr Haworth served as chief executive officer of Intradigm, following his tenure as the company’s vice president of 
business development. He joined Intradigm in 2007, having spent the previous 15 years in senior business development roles at several leading 
biotechnology companies including Genencor International, COR Therapeutics and Affymax/Affymetrix, among others. In these positions, he led the 
identification and negotiation of numerous collaborative and licensing agreements with a range of global and regional pharmaceutical companies. 
He most recently served as vice president, business development at Codexis, Inc. He possesses deep deal‑making expertise that spans establishing 
discovery and development partnerships, technology and product in‑ and out‑licensing, mergers and acquisitions, and financing support. Dr Haworth 
earned his JD from Stanford University Law School and his PhD in biochemistry from the University of Manchester in the UK. 
 Max Herrmann
 Chief Financial Officer and Company Secretary
  Mr Herrmann was appointed Chief Financial Officer of Silence Therapeutics in May 2010. He is a qualified Chartered Accountant and possesses 
more than 20 years of biotechnology and pharmaceutical industry experience having held key management positions with leading development stage 
companies, as well as several investment banks. Prior to joining Silence, Mr Herrmann served as chief financial officer of Intercytex Group plc, a publicly 
traded company focused on the emerging area of regenerative medicine. Before joining Intercytex, he spent over ten years as a sell‑side equity analyst, 
most recently as managing director and head of European pharmaceutical and biotechnology research at ING. He has also held the position of 
financial controller for US‑based Onyx Pharmaceuticals Inc and currently serves on the boards of Regenerative Medicine Assets Limited, as well as 
that company’s subsidiaries Intercytex Ltd. and Axordia Ltd.
 Dr David Mack
 Non‑executive Director
  Dr Mack was appointed as a Non‑executive Director of Silence Therapeutics in January 2010. Prior to his appointment he was a non‑executive 
director of Intradigm Inc. where he was a director since May 2006. He is a director at Alta Partners where he led the investment in Angiosyn as a 
director and acting chief executive officer (acquired by Pfizer in 2005). He is currently on the board of directors of Aerie Pharmaceuticals, Ceregene and 
Proacta. Prior to Alta, Dr Mack co‑founded and served as vice president of Genomics Research at Eos Biotechnology (acquired by Protein Design 
Labs in 2003). From 1995 to 1997, he served at Affymetrix as Head of cancer biology where he oversaw the development and application of DNA 
array technology in the areas of oncology and inflammation. He was also a pivotal member of the Polymerase Chain Reaction (PCR) invention group 
at Cetus (now Chiron) in the mid 1980s. Dr Mack received his PhD in 1992 from the University of Chicago. 
 Dr James Topper
 Non‑executive Director
  Dr Topper Mack was appointed as a non‑executive director of Silence Therapeutics in January 2010. He is a general partner at Frazier Healthcare 
Ventures’ Palo Alto office and was the chairman of the board of Intradigm from May 2006 to the date of the merger with Silence Therapeutics. Since 
joining Frazier Healthcare in 2003, Dr Topper has led several biopharma investments including Arête Therapeutics, Cotherix, and MacuSight. Dr Topper 
is also an advisory board member to the Harvard‑Partners Center for Genetics and Genomics. Prior to joining Frazier Healthcare, he served as head of 
the cardiovascular research and development franchise at Millennium Pharmaceuticals and ran Millennium San Francisco (formerly COR Therapeutics). 
Prior to the merger of COR and Millennium, he served as the Vice President of Biology at COR and was responsible for managing all of its research 
activities. Dr Topper received his MD and PhD in Biophysics from Stanford University School of Medicine in 1991. He continues to hold an 
appointment as a Clinical Assistant Professor of Medicine at Stanford University.
(b)  Resolutions 7 and 8. Your directors may only allot shares or grant rights over shares if authorised to do so by the shareholders. Your Directors also 
require additional authority from shareholders to allot shares or grant rights over shares where they propose to do so for cash or otherwise than to 
existing shareholders pro rata to their holdings. The authorities granted at the last Annual General Meeting on 14 December 2009 are due to expire 
at the Company’s Annual General Meeting in 2010, or on 14 March 2011, whichever is the earlier, and therefore require renewal. These resolutions, 
if passed, will continue to give the directors flexibility to act in the best interest of the shareholders, when the opportunity arises, by issuing new 
shares. Resolution 7 will therefore be proposed as an ordinary resolution to grant a new authority to allot unissued share capital up to an aggregate 
nominal value of £279,891, representing 10% of the total issued ordinary share capital as at 24 May 2010. Resolution 8 will be proposed as a special 
resolution to allot shares or grant rights over shares for cash and otherwise than to existing shareholders pro rata to their holdings. The authority will 
be limited to shares to a maximum aggregate nominal value of £279,891, being 10% of the issued ordinary share capital. These two authorities, 
if given, will expire at the conclusion of the next Annual General Meeting in 2011.
 
Explanatory notes to the notice of Annual 
General Meeting continued 47
Silence Therapeutics plc Annual report and accounts 2009
Review
of the year
Corporate
governance
Financial
statements
Form of proxy
Silence Therapeutics plc
If you will not be attending the Annual General Meeting, or may not do so, you can appoint another person (a “proxy”), who need not be a member of the 
Company, to exercise all or any of your rights to attend, speak and vote at the meeting on your behalf. Completing this form of proxy does not prevent you 
from attending and voting in person.
To be used at the Annual General Meeting to be held on 18 June 2010.
I/We ...................................................................................................................................................................................... (BLOCK LETTERS PLEASE)
of ....................................................................................................................................................................................................................................
being (a) member(s) of the above Company hereby appoint the Chairman of the Meeting, failing whom
..................................................................................................................................................................................................................... (see note 2)
as my/our proxy to vote for me/us on my/our behalf at the Annual General Meeting of the Company to be held on 18 June 2010 at 10.00am and at every 
adjournment thereof.
I/We wish this proxy to be used in connection with those of the resolutions to be proposed at the Annual General Meeting which are listed below, in the 
manner set out below, and in connection with any other business transacted at the meeting.
Dated............................................................................................. 2010 ......................................................................................................... Signature
Please indicate with an X in the spaces below how you wish the proxy to vote. Unless otherwise instructed, the proxy will, at his/her discretion, 
vote as he/she thinks fit or abstain from voting in relation to all business of the Meeting.
Please tick here if this proxy appointment is one of multiple appointments being made  
Resolutions  For  Against  Abstain
1. To receive and approve the accounts for the year ended 31 December 2009.   
2. To reappoint Grant Thornton UK LLP as auditors to the Company.   
3. To re‑elect P . Haworth, who has been appointed since the last Annual General Meeting, as a Director of the Company.   
4. To re‑elect M. Herrmann, who has been appointed since the last Annual General Meeting, as a Director of the Company.   
5. To re‑elect D. Mack, who has been appointed since the last Annual General Meeting, as a Director of the Company.   
6. To re‑elect J. Topper, who has been appointed since the last Annual General Meeting, as a Director of the Company.   
7. To approve the directors’ powers to allot shares for the purposes of Section 551 of the Companies Act 2006.   
8. To approve the directors’ powers to allot shares for cash pursuant to Section 570(1) of the Companies Act 2006.   
Notes
1. This form is for use of shareholders only and will be used only in the event of a poll being directed or demanded.
2. You may if you wish, delete the words ‘the Chairman of the Meeting’ and substitute the name(s) of your choice. Please initial such alteration.
3.  To be valid, this Proxy Form, together with any Power of Attorney under which it is signed or a duly certified copy thereof, should reach the offices of 
the Company’s Registrar, Capita Registrars, not later than 10.00am on 16 June 2010. In the UK, postage on the Proxy Form is prepaid. UK members 
may, if they prefer, return the Proxy Form in an envelope, free of charge, to Capita Registrars PXS, The Registry, 34 Beckenham Road, Beckenham, 
Kent BR3 4TU. Outside the UK, the appropriate postage must be paid.
4. In the case of a corporation, the form must be executed under its common seal or under the hand of an officer or attorney duly authorised in writing.
5.  In the case of joint holders the signature of any of them will suffice, but the names of all joint holders should be shown. The vote of the senior joint 
holder who tenders a vote, whether in person or by proxy, shall be accepted to the exclusion of the votes of the other joint holders, and for this purpose 
seniority shall be determined by the order in which the names stand in the register of members in respect of the joint holding.
6.  A shareholder may appoint more than one proxy in relation to the Annual General Meeting provided that each proxy is appointed to exercise the rights 
attached to a different share or shares held by him. To appoint more than one proxy you may photocopy this form. Please indicate the proxy holder’s 
name and the number of shares in relation to which they are authorised to act as your proxy (which, in aggregate, should not exceed the number of 
shares held by you). Please also indicate if the proxy instruction is one of multiple instructions being given. All forms must be signed and should be 
returned together in the same envelope. A failure to specify the number of shares each proxy appointment relates to or specifying a number in excess 
of those held by you may result in the appointment being invalid. business reply style
Business Reply 
Licence Number 
RSBH-UXKS-LRBC
PXS 
34 Beckenham Road 
Beckenham 
BR3 4TU
first fold
second fold
third fold and tuck in Registered office
22 Melton Street 
London NW1 2BW
Registered number 
2992058
Nominated advisers
Nomura Code Securities Ltd
1 Carey Lane 
London EC2V 8AE
Registrars
Capita IRG plc
Northern House 
Woodsome Park 
Fenay Bridge 
Huddersfield HD8 0LA
Auditor
Grant Thornton UK LLP
Grant Thornton House 
Melton Street 
Euston Square 
London NW1 2EP
Silence Therapeutics plc 
is a leader in the 
of 
novel RNA interference (RNAi) 
therapeutics for the 
RNA interference, a Nobel Prize winning 
technology, is one of the most exciting areas 
of drug discovery today as it can selectively 
“silence” genes linked to the onset of disease, 
thus leading to the creation of a new class of 
therapeutic products, RNAi therapeutics.
We aim to establish Silence Therapeutics 
as a partner-of-choice for the world’s leading 
pharmaceutical companies.
Review of the year
 01  Highlights of 2009
 02  Post year-end highlights
 04 Chairman’s statement
 06 Chief Executive’s review
Corporate governance
 10 Board of directors
 12 Directors’ report
Financial statements
 16 Independent auditors’ report
 17 Consolidated income statement
   Consolidated statement 
of comprehensive income
 18 Consolidated balance sheet
 19   Consolidated statement 
of changes in equity
 20 Company balance sheet
 21   Company statement 
of changes in equity
 22 Cash flow statements
 23 Notes to the financial statements
 43 Company information and advisers
 44 Notice of Annual General Meeting
 45  Explanatory notes to the notice 
of Annual General Meeting
 47 Form of proxy Silence Therapeutics plc
The Royal Institution of Great Britain 
21 Albemarle Street 
London W1S 4BS
Tel:  +44 (0) 20 7491 6520 
Fax:  +44 (0) 20 7491 6521 
email:  mail@silence-therapeutics.com
website: www.silence-therapeutics.com
Silence Therapeutics plc Annual report and accounts 2009
 Silence Therapeutics plc
Annual report  
and accounts 2009