Document:

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                                                                  EXHIBIT 10.1.3

                               BIOVEX GROUP, INC.

             ENTERPRISE MANAGEMENT INCENTIVE STOCK OPTION AGREEMENT
                           FOR UK QUALIFYING EMPLOYEES
                     GRANTED UNDER 2005 STOCK INCENTIVE PLAN

THIS AGREEMENT is made __ day _________________ 200[_]

BETWEEN:

(1)  BIOVEX GROUP, INC., a Delaware corporation (the "COMPANY"); and

(2)  [EMPLOYEE] of [ADDRESS] (the "PARTICIPANT")

WHEREAS:

(A)  The Board (as defined below) considers that the Company is a qualifying
     company as defined in Part 3 of Schedule 5 to the UK Income Tax (Earnings
     and Pensions) Act 2003 ("SCHEDULE 5"). In this agreement, the "Board" shall
     have the same meaning as it carries in the Company's 2005 Stock Incentive
     Plan (the "PLAN"), a copy of which is set out in Exhibit A.

(B)  The Participant is an eligible employee as defined in Part 4 of Schedule 5.

(C)  The Board considers that the grant of this option to the Participant is for
     commercial reasons in order to recruit or retain the Participant and not as
     part of a scheme or arrangement the main purpose, or one of the main
     purposes, of which is the avoidance of tax.

(D)  The Board considers that the total Market Value (as defined below) of
     shares in the Company in respect of which unexercised options (granted in
     respect of the Company's shares which qualify or are intended to qualify as
     enterprise management incentive options under the terms of Schedule 5 ("EMI
     OPTIONS")) subsist does not exceed L3 million or such other value as shall
     be specified at that time in paragraph 7 of Schedule 5. In this agreement,
     "MARKET VALUE" shall be determined in accordance with Part VIII of the
     Taxation of Chargeable Gains Act 1992.

(E)  The Market Value (as at the date of grant) of the shares of common stock
     which the Participant could acquire or has acquired or could have acquired
     by the exercise of:

     (i)  this option, and/or

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     (ii) any other EMI Options granted to him under the Plan or otherwise by
          reason of his employment with any Group Company (as defined below) in
          the preceding three years (whether or not exercised or released),
          and/or

     (iii) any unexercised options to acquire shares under a scheme approved
          under Schedule 4 to the UK Income Tax (Earnings and Pensions) Act 2003
          granted to him by reason of his employment with any Group Company in
          the preceding three years,

     does not exceed L100,000 or such other limit as may be imposed from time to
     time by Schedule 5. The term "GROUP COMPANY" shall include any of the
     Company's present or future parent or subsidiary corporations, and any
     present or future subsidiary corporations of any such present or future
     parent corporations, as defined in Sections 424(e) or (f) of the Code.

(F)  The Company has agreed to grant the Participant an enterprise management
     incentive option to acquire shares of common stock in the capital of the
     Company in accordance with the terms of Schedule 5 and on the terms set out
     in this agreement and the Plan.

(G)  The restrictions to which the Shares may be subject are set out in: (i) the
     Company's certificate of incorporation, as amended from time to time (a
     copy of which is set out in Exhibit B), (ii) the terms set forth in the
     Notice of Exercise as amended from time to time (a copy of which is set out
     in Exhibit C), (iii) the Company's Stockholders' Agreement dated as of 30
     August 2005 as amended or substituted from time to time (a copy of which is
     set out in Exhibit D to this agreement) and (iv) this agreement and the
     Plan generally.

1.   Grant of Option.

     This agreement evidences the grant by BioVex Group, Inc., a Delaware
corporation (the "COMPANY"), on _______, 200[_] (the "GRANT DATE") to [_______],
an employee of the Company or one of its wholly owned subsidiaries (the
"PARTICIPANT"), of an option to purchase, in whole or in part, on the terms on
the terms of Schedule 5 and as provided herein and in the Plan, a total of [___]
shares (the "SHARES") of common stock, $0.0001 par value per share, of the
Company ("COMMON STOCK") at $[______] per Share. Unless earlier terminated, this
option shall expire at 5:00 p.m., Eastern time, on the day immediately preceding
the tenth anniversary of the Grant Date (the "FINAL EXERCISE DATE").

     It is intended that the option evidenced by this agreement shall not be an
incentive stock option as defined in Section 422 of the Internal Revenue Code of
1986, as amended, and any regulations promulgated thereunder (the "CODE").
Except as otherwise indicated by the context, the term "Participant", as used in
this option, shall be deemed to include any person who acquires the right to
exercise this option validly under its terms.

     The Participant shall within 30 days (or such longer period as permitted by
the Board) immediately following the Grant Date give a declaration to the
Company (in the form determined by the Board) that he meets the requirements of
paragraph 26 of Schedule 5 (commitment of working time) in relation to this
option. If the Participant fails to provide the

                                       -2-

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declaration referred to above within such period, the Board shall give at least
7 days' notice to the Participant requiring him to provide such declaration and
if the Participant fails to provide that declaration by the expiry of the
notice, the Board may in its absolute discretion determine that this option
shall lapse immediately and be deemed never to have been granted.

     The Company will procure that notice of the grant of this option shall
within 92 days after the Grant Date be given to HM Revenue & Customs by the
company by which the Participant is employed. Such notice shall be in a form
required or authorised by the Inland Revenue and must contain, or be supported
by, such information as the Inland Revenue may require including the
declarations under paragraph 44(5) of Schedule 5.

2.   Vesting Schedule.

     (a) Time based vesting. Subject always to Section 2(b), this option will
become exercisable ("vest") as to one-quarter (1/4) of the original number of
Shares on the first anniversary of the Grant Date and as to an additional
one-forty-eighth (1/48th) of the original number of Shares at the end of each
successive one-month period following the first anniversary of the Grant Date
until the fourth anniversary of the Grant Date.]

     Subject always to Section 2(b), the right of exercise shall be cumulative
so that to the extent the option is not exercised in any period to the maximum
extent permissible it shall continue to be exercisable, in whole or in part,
with respect to all Shares for which it is vested until the earlier of the Final
Exercise Date or the termination of this option under Section 3 hereof or the
Plan.

     (b) Overriding requirement for Listing, etc. Notwithstanding anything to
the contrary in this agreement or the Plan, no part of this option may be
exercised unless and until a Listing (as defined in Plan) has taken effect or
the option becomes exercisable as a result of the application of Section 8(b)(2)
of the Plan (change of control - effect on options).

3.   Exercise of Option.

     (a) Form of Exercise. Each election to exercise this option shall be in
writing, in the form of Exhibit C, signed by the Participant, and received by
the Company at its principal office, accompanied by this agreement, and payment
in full in the manner provided in the Plan. The Participant may purchase fewer
than the number of shares covered hereby, provided that no partial exercise of
this option may be for any fractional share.

     (b) Continuous Relationship with the Company Required. Except as otherwise
provided in this Section 3 and subject to Section 2(b) above, this option may
not be exercised unless the Participant, at the time he or she exercises this
option, is, and has been at all times since the Grant Date, an employee or
officer of, or consultant or advisor to, the Company or any parent or subsidiary
of the Company as defined in Section 424(e) or (f) of the Code (an "ELIGIBLE
PARTICIPANT").

     (c) Termination of Relationship with the Company. If the Participant ceases
to be an Eligible Participant for any reason, then, except as provided in
paragraphs (d) and (e) below, this option shall terminate three months after
such cessation (but in no event after the Final Exercise

                                       -3-

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Date), provided that this option shall be exercisable (subject to Section 2(b)
above) only to the extent that this option was vested in accordance with Section
2(a) above on the date of such cessation. Notwithstanding the foregoing, if the
Participant, prior to the Final Exercise Date, violates the non-competition or
confidentiality provisions of any employment contract, confidentiality and
nondisclosure agreement or other agreement between the Participant and the
Company, any right to exercise this option and the option itself shall terminate
immediately upon such violation.

     (d) Exercise Period Upon Death or Disability. If the Participant dies or
becomes disabled (within the meaning of Section 22(e)(3) of the Code) prior to
the Final Exercise Date while he or she is an Eligible Participant and the
Company has not terminated such relationship for "cause" as specified in
paragraph (e) below, this option shall be exercisable (subject to Section 2(b)
above), within the period of one year following the date of death or disability
of the Participant, by the Participant (or in the case of death by an authorized
transferee), provided that this option shall be exercisable (subject to Section
2(b) above) only to the extent that this option was vested in accordance with
Section 2(a) above on the date of the Participant's death or disability, and
further provided that this option shall not be exercisable after the Final
Exercise Date.

     (e) Discharge for Cause. If the Participant, prior to the Final Exercise
Date, is discharged by the Company for "cause" (as defined below), any right to
exercise this option and the option itself shall terminate immediately upon the
effective date of such discharge. "CAUSE" shall mean willful misconduct by the
Participant or willful failure by the Participant to perform his or her
responsibilities to the Company (including, without limitation, any material
breach by the Participant of any provision of any employment, consulting,
advisory, nondisclosure, non-competition or other similar agreement between the
Participant and the Company), as determined by the Company, which determination
shall be conclusive. The Participant shall be considered to have been discharged
for "Cause" if the Company determines, within 30 days after the Participant's
resignation, that discharge for cause was warranted.

     (f) Conditions on Delivery of Stock. The Company will not be obligated to
deliver any shares of Common Stock pursuant to this agreement until (i) all
conditions of this option have been met to the satisfaction of the Company; (ii)
in the opinion of the Company's counsel, all other legal matters in connection
with the issuance and delivery of such shares have been satisfied, including any
applicable securities laws and any applicable stock exchange or stock market
rules and regulations; (iii) the Participant has become a party to, and become
bound as a "Common Holder" under, the Company's Stockholders' Agreement, dated
as of 30 August 2005 and as amended or substituted from time to time, by
executing a counterpart signature page in substantially the form of Exhibit E;
and (iv) the Participant has executed and delivered to the Company such
additional representations or agreements as the Company may consider appropriate
to satisfy the requirements of any applicable laws, rules or regulations.

     (g) Employer national insurance. This option may not be exercised unless
and until the Company (or any Group Company) has received from the Participant
duly executed documentation (in such form as prescribed by the Board from time
to time) to the effect that the Participant will become liable, so far as
permissible by law, for the whole of any secondary Class

                                       -4-

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1 national insurance contributions which may arise in connection with this
option and the shares of common stock which may or are acquired on the exercise
of this option.

     (h) Restricted Shares Election. Unless the Board permits otherwise, this
option may not be exercised unless and until the Participant enters into a joint
election under Section 431(1) of the Income Tax (Earnings and Pensions) Act 2003
(in the form prescribed by the Board from time to time) for the full
disapplication of Chapter 2 of Part 7 of that Act.

4.   No Obligation to Recognize Invalid Transfer.

     The Company shall not be required (1) to transfer on its books any of the
Shares which shall have been sold or transferred in violation of any of the
provisions set forth in the Stockholders' Agreement, or (2) to treat as owner of
such Shares or to pay dividends to any transferee to whom any such Shares shall
have been so sold or transferred.

5.   Tax Matters.

     (a) Withholding. No Shares will be issued pursuant to the exercise of this
option unless and until the Participant pays to the Company, or makes provision
satisfactory to the Company for payment of, any federal, state or local
withholding taxes required by law to be withheld in respect of this option.

     (b) Tax status. Neither the Company nor any parent or subsidiary of the
Company shall have any liability to the Participant if this option (or any part
thereof) is not or ceases to be a qualifying option under schedule 5 to the
Income Tax (Earnings and Pensions) Act 2003.

6.   Nontransferability of Option.

     This option may not be sold, assigned, transferred, pledged or otherwise
encumbered by the Participant, either voluntarily or by operation of law, except
by will or the laws of descent and distribution, and, during the lifetime of the
Participant, this option shall be exercisable only by the Participant.

7.   No Right to Employment etc.

     (a) The grant of options under the Plan is made at the discretion of the
Board and the Plan may be suspended or terminated by the Company at any time.
The grant of an option in one year or at one time does not in any way entitle
the Participant to an option grant in the future. The Plan is wholly
discretionary and is not to be considered part of the Participant's normal or
expected compensation subject to severance, resignation, redundancy or similar
compensation. The value of the option is an extraordinary item of compensation
which is outside the scope of the Participant's employment contract (if any).

     (b) Nothing in this agreement or the Plan shall confer upon the Participant
any right to continue in service for any period of specific duration or
interfere with or otherwise restrict in any way the rights of the Company (or
any company employing or retaining the Participant) or of the Participant, which
rights are hereby expressly reserved by each, to terminate the Participant's
service at any time for any reason, with or without cause.

                                       -5-

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     (c) The rights and obligations of the Participant under the terms of his
office or employment with the Company, any past or present subsidiary, or
associated or affiliate company of the Company shall not be affected by his
participation in the Plan or the grant of this option or any right which he may
have to participate therein, and the Participant hereby waives all and any
rights to compensation or damages in consequence of the termination of his
office or employment with any such company for any reasons whatsoever (whether
lawful or unlawful and including, without prejudice to the generality of the
foregoing, in circumstances giving rise to a claim for wrongful dismissal)
insofar as those rights arise or may arise from his ceasing to have rights under
or being entitled to exercise this option as a result of such termination, or
from the loss or diminution in value of such rights or entitlements.

8.   Data Protection.

     The Participant agrees to the receipt, holding and processing of
information in connection with the grant, vesting, exercise, taxation and
general administration of the Plan and this option by the Company or any
subsidiary of the Company and any of their advisers or agents and to the
transmission of such information outside of the European Economic Area for this
purpose.

9.   Provisions of the Plan.

     This option is subject to the provisions of the Plan, a copy of which is
furnished to the Participant with this option.

10.  Third Party Rights.

     The Contracts (Rights of Third Parties) Act 1999 shall not apply to this
option and no person other than parties hereto shall have any rights under it
nor shall it be enforceable under that Act by any person other than the parties
to it.

                                      *****

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     IN WITNESS WHEREOF, the parties have executed this agreement as a Deed on
the date first above written. This agreement shall take effect as a deed and a
sealed instrument.

                                        BIOVEX GROUP, INC.

                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------

EXECUTED as a DEED by PARTICIPANT:      By:
                                            ------------------------------------
                                            (Signature of Participant)

                                        Name:
                                              ----------------------------------
                                              (Printed Name of Participant)

In the presence of:

Witness signature:
                   ------------------
Witness name:
              -----------------------
Witness address:
                 --------------------

                 --------------------
Witness occupation:
                    -----------------

                                       -7-

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                                    EXHIBIT A

                            2005 STOCK INCENTIVE PLAN

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                                    EXHIBIT B

                          CERTIFICATE OF INCORPORATION

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                                    EXHIBIT C

                         NOTICE OF STOCK OPTION EXERCISE

                              Date: ____________(1)

BioVex Group, Inc.
Attention: Treasurer
Dear Sir or Madam:

     I am the holder of Stock Option granted to me under the BioVex Group, Inc.
(the "Company") 2005 Stock Incentive Plan on __________(2) for the purchase of
__________(3) shares of Common Stock of the Company at a purchase price of
$__________(4) per share.

     I hereby exercise my option to purchase _________(5) shares of Common Stock
(the "Shares"), for which I have enclosed __________(6) in the amount of
________(7). Please register my stock certificate as follows:

     Name(s): __________________________(8)
              __________________________
     Address: __________________________

     Tax I.D. #: _______________________(9)

     I represent, warrant and covenant as follows:

----------
(1)  Enter the date of exercise.

(2)  Enter the date of grant.

(3)  Enter the total number of shares of Common Stock for which the option was
     granted.

(4)  Enter the option exercise price per share of Common Stock.

(5)  Enter the number of shares of Common Stock to be purchased upon exercise of
     all or part of the option.

(6)  Enter "cash", "personal check" or if permitted by the option or Plan,
     "stock certificates No. XXXX and XXXX".

(7)  Enter the dollar amount (price per share of Common Stock times the number
     of shares of Common Stock to be purchased), or the number of shares
     tendered. Fair market value of shares tendered, together with cash or
     check, must cover the purchase price of the shares issued upon exercise.

(8)  Enter name(s) to appear on stock certificate: (a) Your name only; (b) Your
     name and other name (i.e., John Doe and Jane Doe, Joint Tenants With Right
     of Survivorship); or (c) In the case of a Nonstatutory option only, a
     Child's name, with you as custodian (i.e., Jane Doe, Custodian for Tommy
     Doe). Note: There may be income and/or gift tax consequences of registering
     shares in a Child's name.

(9)  Social Security Number of Holder(s).

<PAGE>

1. I am purchasing the Shares for my own account for investment only, and not
with a view to, or for sale in connection with, any distribution of the Shares
in violation of the Securities Act of 1933 (the "Securities Act"), or any rule
or regulation under the Securities Act.

2. I have had such opportunity as I have deemed adequate to obtain from
representatives of the Company such information as is necessary to permit me to
evaluate the merits and risks of my investment in the Company.

3. I have sufficient experience in business, financial and investment matters to
be able to evaluate the risks involved in the purchase of the Shares and to make
an informed investment decision with respect to such purchase.

4. I can afford a complete loss of the value of the Shares and am able to bear
the economic risk of holding such Shares for an indefinite period.

5. I understand that (i) the Shares have not been registered under the
Securities Act and are "restricted securities" within the meaning of Rule 144
under the Securities Act, (ii) the Shares cannot be sold, transferred or
otherwise disposed of unless they are subsequently registered under the
Securities Act or an exemption from registration is then available; (iii) in any
event, the exemption from registration under Rule 144 will not be available for
at least one year and even then will not be available unless a public market
then exists for the Common Stock, adequate information concerning the Company is
then available to the public, and other terms and conditions of Rule 144 are
complied with; and (iv) there is now no registration statement on file with the
Securities and Exchange Commission with respect to any stock of the Company and
the Company has no obligation or current intention to register the Shares under
the Securities Act.

Very truly yours,

----------------------------------------
(Signature)

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                                    EXHIBIT D

                             STOCKHOLDERS' AGREEMENT

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                                    EXHIBIT E

                               BIOVEX GROUP, INC.

                           COUNTERPART SIGNATURE PAGE

     The undersigned, a holder of common stock of BioVex Group, Inc., a Delaware
corporation (the "Company"), hereby agrees to become a party to, and to be bound
as a "Common Holder" under the Company's Stockholders' Agreement, originally
entered into among the Company and certain of its stockholders as of 30 August
2005, a copy of which is attached hereto as Annex A.

     EXECUTED as of __________, 200[_].

                                        ----------------------------------------
                                        (Signature)

                                        ----------------------------------------
                                        (Printed name)<PAGE>

                                                                  EXHIBIT 10.1.4

                               BIOVEX GROUP, INC.

                           RESTRICTED STOCK AGREEMENT
                                FOR US EMPLOYEES
                     GRANTED UNDER 2005 STOCK INCENTIVE PLAN

     AGREEMENT made this 30th day of August, 2005, between BioVex Group, Inc, a
Delaware corporation (the "Company"), and Philip Astley-Sparke (the
"Participant").

     For valuable consideration, receipt of which is acknowledged, the parties
hereto agree as follows:

     1.   Purchase of Shares.

     The Company shall issue and sell to the Participant, and the Participant
shall purchase from the Company, subject to the terms and conditions set forth
in this Agreement and in the Company's 2005 Stock Incentive Plan (the "Plan"),
800,000 shares (the "Shares") of common stock, $0.0001 par value, of the Company
("Common Stock"), at a purchase price of $0.0001 per share. The aggregate
purchase price for the Shares shall be paid by the Participant by check payable
to the order of the Company or such other method as may be acceptable to the
Company. Upon receipt by the Company of payment for the Shares, the Company
shall issue to the Participant one or more certificates in the name of the
Participant for that number of Shares purchased by the Participant. The
Participant agrees that the Shares shall be subject to the purchase option set
forth in Section 2 of this Agreement and the restrictions on transfer set forth
in Section 4 of this Agreement.

     2.   Purchase Option.

          (a) In the event that the Participant ceases to be employed by the
Company for any reason or no reason, with or without cause, prior to the earlier
of the date on which a Listing takes effect or immediately prior to a Change of
Control, the Company shall have the right and option (the "Purchase Option") to
purchase from the Participant, for a sum of $0.0001 per share (the "Option
Price"), some or all of the Unvested Shares (as defined below).

     "Unvested Shares" means the total number of Shares multiplied by the
Applicable Percentage at the time the Purchase Option becomes exercisable by the
Company. The "Applicable Percentage" shall be 100% prior to the earlier of a
Listing taking effect or immediately prior to a Change of Control and 0%
thereafter.

          (b) For purposes of this Agreement, the Participant's employment with
the Company shall not be considered to have terminated if he or she remains
employed by a parent or subsidiary of the Company.

     3.   Exercise of Purchase Option and Closing.

<PAGE>

          (a) The Company may exercise the Purchase Option by delivering or
mailing to the Participant (or his estate), within 90 days after the termination
of the employment of the Participant with the Company, a written notice of
exercise of the Purchase Option. Such notice shall specify the number of Shares
to be purchased. If and to the extent the Purchase Option is not so exercised by
the giving of such a notice within such 90-day period, the Purchase Option shall
automatically expire and terminate effective upon the expiration of such 90-day
period.

          (b) Within 10 days after delivery to the Participant of the Company's
notice of the exercise of the Purchase Option pursuant to subsection (a) above,
the Participant (or his estate) shall, pursuant to the provisions of the Joint
Escrow Instructions referred to in Section 6 below, tender to the Company at its
principal offices the certificate or certificates representing the Shares which
the Company has elected to purchase in accordance with the terms of this
Agreement, duly endorsed in blank or with duly endorsed stock powers attached
thereto, all in form suitable for the transfer of such Shares to the Company.
Promptly following its receipt of such certificate or certificates, the Company
shall pay to the Participant the aggregate Option Price for such Shares
(provided that any delay in making such payment shall not invalidate the
Company's exercise of the Purchase Option with respect to such Shares).

          (c) After the time at which any Shares are required to be delivered to
the Company for transfer to the Company pursuant to subsection (b) above, the
Company shall not pay any dividend to the Participant on account of such Shares
or permit the Participant to exercise any of the privileges or rights of a
stockholder with respect to such Shares, but shall, in so far as permitted by
law, treat the Company as the owner of such Shares.

          (d) The Option Price may be payable, at the option of the Company, in
cancellation of all or a portion of any outstanding indebtedness of the
Participant to the Company or in cash (by check) or both.

          (e) The Company shall not purchase any fraction of a Share upon
exercise of the Purchase Option, and any fraction of a Share resulting from a
computation made pursuant to Section 2 of this Agreement shall be rounded to the
nearest whole Share (with any one-half Share being rounded upward).

          (f) The Company may assign its Purchase Option to one or more persons
or entities.

     4.   Restrictions on Transfer.

     The Participant shall not sell, assign, transfer, pledge, hypothecate or
otherwise dispose of, by operation of law or otherwise (collectively "transfer")
any Shares, or any interest therein, that are subject to the Purchase Option,
except that the Participant may transfer such Shares (i) to or for the benefit
of any spouse, children, parents, uncles, aunts, siblings, grandchildren and any
other relatives approved by the Board of Directors (collectively, "Approved
Relatives") or to a trust established solely for the benefit of the Participant
and/or Approved Relatives, provided that such Shares shall remain subject to
this Agreement (including without limitation the restrictions on transfer set
forth in this Section 4 and the Purchase Option) and such permitted transferee
shall, as a condition to such transfer, deliver to the Company a written
instrument confirming

                                       -2-

<PAGE>

that such transferee shall be bound by all of the terms and conditions of this
Agreement or (ii) as part of the sale of all or substantially all of the shares
of capital stock of the Company (including pursuant to a merger or
consolidation), provided that, in accordance with the Plan, the securities or
other property received by the Participant in connection with such transaction
shall remain subject to this Agreement.

     5.   Stockholders' Agreement

     The Participant shall, upon execution of this Agreement, become a party to,
and be bound as a "Common Holder" under, the Company's Stockholders' Agreement,
dated as of 30 August 2005 and as amended or substituted from time to time, by
executing a counterpart signature page in substantially the form of Exhibit A.

     6.   Escrow.

     The Participant shall, upon the execution of this Agreement, execute Joint
Escrow Instructions in the form attached to this Agreement as Exhibit B. The
Joint Escrow Instructions shall be delivered to the Secretary of the Company, as
escrow agent thereunder. The Participant shall deliver to such escrow agent a
stock assignment duly endorsed in blank, in the form attached to this Agreement
as Exhibit C, and hereby instructs the Company to deliver to such escrow agent,
on behalf of the Participant, the certificate(s) evidencing the Shares issued
hereunder. Such materials shall be held by such escrow agent pursuant to the
terms of such Joint Escrow Instructions.

     7.   Restrictive Legends.

     All certificates representing Shares shall have affixed thereto legends in
substantially the following form, in addition to any other legends that may be
required under federal or state securities laws:

          "The shares of stock represented by this certificate are subject to
          restrictions on transfer and an option to purchase set forth in a
          certain Restricted Stock Agreement between the corporation and the
          registered owner of these shares (or his predecessor in interest), and
          such Agreement is available for inspection without charge at the
          office of the Secretary of the corporation."

          "The shares represented by this certificate have not been registered
          under the Securities Act of 1933, as amended, and may not be sold,
          transferred or otherwise disposed of in the absence of an effective
          registration statement under such Act or an opinion of counsel
          satisfactory to the corporation to the effect that such registration
          is not required."

     8.   Provisions of the Plan.

     This Agreement is subject to the provisions of the Plan, a copy of which is
furnished to the Participant with this Agreement.

                                       -3-

<PAGE>

     9.   Investment Representations.

     The Participant represents, warrants and covenants as follows:

          (a) The Participant is purchasing the Shares for his own account for
investment only, and not with a view to, or for sale in connection with, any
distribution of the Shares in violation of the Securities Act of 1933 (the
"Securities Act"), or any rule or regulation under the Securities Act.

          (b) The Participant has had such opportunity as he has deemed adequate
to obtain from representatives of the Company such information as is necessary
to permit him to evaluate the merits and risks of his investment in the Company.

          (c) The Participant has sufficient experience in business, financial
and investment matters to be able to evaluate the risks involved in the purchase
of the Shares and to make an informed investment decision with respect to such
purchase.

          (d) The Participant can afford a complete loss of the value of the
Shares and is able to bear the economic risk of holding such Shares for an
indefinite period.

          (e) The Participant understands that (i) the Shares have not been
registered under the Securities Act and are "restricted securities" within the
meaning of Rule 144 under the Securities Act; (ii) the Shares cannot be sold,
transferred or otherwise disposed of unless they are subsequently registered
under the Securities Act or an exemption from registration is then available;
(iii) in any event, the exemption from registration under Rule 144 will not be
available for at least one year and even then will not be available unless a
public market then exists for the Common Stock, adequate information concerning
the Company is then available to the public, and other terms and conditions of
Rule 144 are complied with; and (iv) there is now no registration statement on
file with the Securities and Exchange Commission with respect to any stock of
the Company and the Company has no obligation or current intention to register
the Shares under the Securities Act.

     10.  Withholding Taxes; Section 83(b) Election and indemnity, etc.

          (a) The Participant acknowledges and agrees that the Company has the
right to deduct from payments of any kind otherwise due to the Participant any
federal, state or local taxes or social security of any kind (whether US or
otherwise) (together "Taxes") required by law to be withheld or paid on behalf
of or in respect of the Participant with respect to the purchase of the Shares
by the Participant or the lapse of the Purchase Option.

          (b) The Participant has reviewed with the Participant's own tax
advisors the federal, state, local and foreign tax consequences of this
investment and the transactions contemplated by this Agreement. The Participant
is relying solely on such advisors and not on any statements or representations
of the Company or any of its agents. The Participant understands that the
Participant (and not the Company) shall be responsible for the Participant's own
tax liability that may arise as a result of this investment or the transactions
contemplated by this Agreement. The Participant understands that it may be
beneficial in many circumstances to elect to be taxed at the time the Shares are
purchased rather than when and as the Company's

                                       -4-

<PAGE>

Purchase Option expires by filing an election under Section 83(b) of the
Internal Revenue Code of 1986 with the I.R.S. within 30 days from the date of
purchase.(1)

          THE PARTICIPANT ACKNOWLEDGES THAT IT IS THE PARTICIPANT'S SOLE
RESPONSIBILITY AND NOT THE COMPANY'S TO FILE TIMELY THE ELECTION UNDER SECTION
83(b), EVEN IF THE PARTICIPANT REQUESTS THE COMPANY OR ITS REPRESENTATIVES TO
MAKE THIS FILING ON THE PARTICIPANT'S BEHALF.

          (c) The Participant shall join with the Company and/or such other
company determined by the Company in electing, pursuant to section 431 of the UK
Income Tax (Earnings and Pensions) Act 2003 ("ITEPA") and in the form determined
by the Company from time to time, that for the relevant tax purposes the market
value of the Shares acquired pursuant to this Agreement shall be calculated as
they were not restricted and sections 425 to 430 of ITEPA (inclusive) do not
apply.

          (d) The Company hereby agrees to indemnify the Participant in relation
to income or capital gains tax which arises directly as a result of a
disposition of the Shares in relation to a Change of Control which occurs within
12 months of the date of this Agreement, but only to the extent of any such tax
assessed at a rate exceeding 15% of the value of the gain on any such
disposition.

     11.  Miscellaneous.

          (a) No Rights to Employment. The Participant acknowledges and agrees
that the vesting of the Shares pursuant to Section 2 hereof is earned only by
continuing service as an employee at the will of the Company (not through the
act of being hired or purchasing shares hereunder). The Participant further
acknowledges and agrees that the transactions contemplated hereunder and the
vesting schedule set forth herein do not constitute an express or implied
promise of continued engagement as an employee or consultant for the vesting
period, for any period, or at all.

          (b) Severability. The invalidity or unenforceability of any provision
of this Agreement shall not affect the validity or enforceability of any other
provision of this Agreement, and each other provision of this Agreement shall be
severable and enforceable to the extent permitted by law.

          (c) Waiver. Any provision for the benefit of the Company contained in
this Agreement may be waived, either generally or in any particular instance, by
the Board of Directors of the Company.

          (d) Binding Effect. This Agreement shall be binding upon and inure to
the benefit of the Company and the Participant and their respective heirs,
executors, administrators, legal representatives, successors and assigns,
subject to the restrictions on transfer set forth in Sections 4 and 5 of this
Agreement.

----------
(1)  If the Shares are sold to the Participant for a purchase price equal to
     their fair market value at the time of such sale, a Section 83(b) election
     will almost always be advisable.

                                       -5-

<PAGE>

          (e) Notice. All notices required or permitted hereunder shall be in
writing and deemed effectively given upon personal delivery or five days after
deposit in the United States Post Office, by registered or certified mail,
postage prepaid, addressed to the other party hereto at the address shown
beneath his or its respective signature to this Agreement, or at such other
address or addresses as either party shall designate to the other in accordance
with this Section 12(e).

          (f) Pronouns. Whenever the context may require, any pronouns used in
this Agreement shall include the corresponding masculine, feminine or neuter
forms, and the singular form of nouns and pronouns shall include the plural, and
vice versa.

          (g) Entire Agreement. This Agreement and the Plan constitute the
entire agreement between the parties, and supersedes all prior agreements and
understandings, relating to the subject matter of this Agreement.

          (h) Amendment. This Agreement may be amended or modified only by a
written instrument executed by both the Company and the Participant.

          (i) Governing Law. This Agreement shall be construed, interpreted and
enforced in accordance with the internal laws of the State of Delaware without
regard to any applicable conflicts of laws.

          (j) Participant's Acknowledgments. The Participant acknowledges that
he or she: (i) has read this Agreement; (ii) has been represented in the
preparation, negotiation, and execution of this Agreement by legal counsel of
the Participant's own choice or has voluntarily declined to seek such counsel;
(iii) understands the terms and consequences of this Agreement; (iv) is fully
aware of the legal and binding effect of this Agreement; and (v) understands
that the law firm of Wilmer Cutler Pickering Hale and Dorr LLP, is acting as
counsel to the Company in connection with the transactions contemplated by the
Agreement, and is not acting as counsel for the Participant.

     IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
the day and year first above written.

                                         BIOVEX GROUP, INC.

                                         By: /s/ Garethy Beynon
                                             -----------------------------------
                                         Title: Chief Executive Officer
                                         Address: 1 Softwell Manor, Baker's Lane
                                                  Brightwell-cum-Sotwell, UK

                                         /s/ Philip Astley-Sparke
                                         ---------------------------------------
                                         Philip Astley-Sparke
                                         Address: 8 Amanda Lane
                                                  Weston, MA 02493

                                       -6-

<PAGE>

                                    EXHIBIT A

                               BIOVEX GROUP, INC.

                           COUNTERPART SIGNATURE PAGE

     The undersigned, a holder of common stock of BioVex Group, Inc., a Delaware
corporation (the "Company"), hereby agrees to become a party to, and to be bound
as a "Common Holder" under the Company's Stockholders' Agreement, originally
entered into among the Company and certain of its stockholders as of 30 August
2005, a copy of which is attached hereto as Annex A.

     EXECUTED as of __________, 200[_].

                                         ---------------------------------------
                                         (Signature)

                                         ---------------------------------------
                                         (Printed name)

                                       -7-

<PAGE>

                                    EXHIBIT B

                               BIOVEX GROUP, INC.

                            Joint Escrow Instructions

                               ___________, [____]

Secretary
BioVex Group, Inc.

Dear Sir:

     As Escrow Agent for BioVex Group, Inc., a Delaware corporation, and its
successors in interest under the Restricted Stock Agreement (the "Agreement") of
even date herewith, to which a copy of these Joint Escrow Instructions is
attached (the "Company"), and the undersigned person ("Holder"), you are hereby
authorized and directed to hold the documents delivered to you pursuant to the
terms of the Agreement in accordance with the following instructions:

     1. Appointment. Holder irrevocably authorizes the Company to deposit with
you any certificates evidencing Shares (as defined in the Agreement) to be held
by you hereunder and any additions and substitutions to said Shares. For
purposes of these Joint Escrow Instructions, "Shares" shall be deemed to include
any additional or substitute property. Holder does hereby irrevocably constitute
and appoint you as his attorney-in-fact and agent for the term of this escrow to
execute with respect to such Shares all documents necessary or appropriate to
make such Shares negotiable and to complete any transaction herein contemplated.
Subject to the provisions of this Section 1 and the terms of the Agreement,
Holder shall exercise all rights and privileges of a stockholder of the Company
while the Shares are held by you.

     2. Closing of Purchase.

          (a) Upon any purchase by the Company of the Shares pursuant to the
Agreement, the Company shall give to Holder and you a written notice specifying
the purchase price for the Shares, as determined pursuant to the Agreement, and
the time for a closing hereunder (the "Closing") at the principal office of the
Company. Holder and the Company hereby irrevocably authorize and direct you to
close the transaction contemplated by such notice in accordance with the terms
of said notice.

          (b) At the Closing, you are directed (i) to date the stock assignment
form or forms necessary for the transfer of the Shares, (ii) to fill in on such
form or forms the number of Shares being transferred, and (iii) to deliver same,
together with the certificate or certificates

                                       -8-

<PAGE>

evidencing the Shares to be transferred, to the Company against the simultaneous
delivery to you of the purchase price for the Shares being purchased pursuant to
the Agreement.

     3. Withdrawal. The Holder shall have the right to withdraw from this escrow
any Shares as to which the Purchase Option (as defined in the Agreement) has
terminated or expired.(2)

     4. Duties of Escrow Agent.

          (a) Your duties hereunder may be altered, amended, modified or revoked
only by a writing signed by all of the parties hereto.

          (b) You shall be obligated only for the performance of such duties as
are specifically set forth herein and may rely and shall be protected in relying
or refraining from acting on any instrument reasonably believed by you to be
genuine and to have been signed or presented by the proper party or parties. You
shall not be personally liable for any act you may do or omit to do hereunder as
Escrow Agent or as attorney-in-fact of Holder while acting in good faith and in
the exercise of your own good judgment, and any act done or omitted by you
pursuant to the advice of your own attorneys shall be conclusive evidence of
such good faith.

          (c) You are hereby expressly authorized to disregard any and all
warnings given by any of the parties hereto or by any other person or entity,
excepting only orders or process of courts of law, and are hereby expressly
authorized to comply with and obey orders, judgments or decrees of any court. If
you are uncertain of any actions to be taken or instructions to be followed, you
may refuse to act in the absence of an order, judgment or decrees of a court. In
case you obey or comply with any such order, judgment or decree of any court,
you shall not be liable to any of the parties hereto or to any other person or
entity, by reason of such compliance, notwithstanding any such order, judgment
or decree being subsequently reversed, modified, annulled, set aside, vacated or
found to have been entered without jurisdiction.

          (d) You shall not be liable in any respect on account of the identity,
authority or rights of the parties executing or delivering or purporting to
execute or deliver the Agreement or any documents or papers deposited or called
for hereunder.

          (e) You shall be entitled to employ such legal counsel and other
experts as you may deem necessary properly to advise you in connection with your
obligations hereunder and may rely upon the advice of such counsel.

          (f) Your rights and responsibilities as Escrow Agent hereunder shall
terminate if (i) you cease to be Secretary of the Company or (ii) you resign by
written notice to each party. In the event of a termination under clause (i),
your successor as Secretary shall become Escrow Agent hereunder; in the event of
a termination under clause (ii), the Company shall appoint a successor Escrow
Agent hereunder.

----------
(2)  If there is a Right of First Refusal in addition to the Purchase Option,
     consideration should be given to extending the escrow to cover the period
     of time when the Right of First Refusal remains in effect.

                                       -9-

<PAGE>

          (g) If you reasonably require other or further instruments in
connection with these Joint Escrow Instructions or obligations in respect
hereto, the necessary parties hereto shall join in furnishing such instruments.

          (h) It is understood and agreed that if you believe a dispute has
arisen with respect to the delivery and/or ownership or right of possession of
the securities held by you hereunder, you are authorized and directed to retain
in your possession without liability to anyone all or any part of said
securities until such dispute shall have been settled either by mutual written
agreement of the parties concerned or by a final order, decree or judgment of a
court of competent jurisdiction after the time for appeal has expired and no
appeal has been perfected, but you shall be under no duty whatsoever to
institute or defend any such proceedings.

          (i) These Joint Escrow Instructions set forth your sole duties with
respect to any and all matters pertinent hereto and no implied duties or
obligations shall be read into these Joint Escrow Instructions against you.

          (j) The Company shall indemnify you and hold you harmless against any
and all damages, losses, liabilities, costs, and expenses, including attorneys'
fees and disbursements, (including without limitation the fees of counsel
retained pursuant to Section 4(e) above, for anything done or omitted to be done
by you as Escrow Agent in connection with this Agreement or the performance of
your duties hereunder, except such as shall result from your gross negligence or
willful misconduct.

     5. Notice. Any notice required or permitted hereunder shall be given in
writing and shall be deemed effectively given upon personal delivery or upon
deposit in the United States Post Office, by registered or certified mail with
postage and fees prepaid, addressed to each of the other parties thereunto
entitled at the following addresses, or at such other addresses as a party may
designate by ten days' advance written notice to each of the other parties
hereto.

          COMPANY:      Notices to the Company shall be sent to the
                        address set forth in the salutation hereto, Attn:
                        President

          HOLDER:       Notices to Holder shall be sent to the address
                        set forth below Holder's signature below.

          ESCROW AGENT: Notices to the Escrow Agent shall be sent to the
                        address set forth in the salutation hereto.

     6. Miscellaneous.

          (a) By signing these Joint Escrow Instructions, you become a party
hereto only for the purpose of said Joint Escrow Instructions, and you do not
become a party to the Agreement.

                                      -10-

<PAGE>

          (b) This instrument shall be binding upon and inure to the benefit of
the parties hereto and their respective successors and permitted assigns.

                                         Very truly yours,

                                         BioVex Group, Inc.

                                         By:
                                             -----------------------------------
                                         Title:

                                         HOLDER:

                                         ---------------------------------------

                                         Print Name

                                         Address:

                                         Date Signed:

ESCROW AGENT:

--------------------------------------

                                      -11-

<PAGE>

                                    EXHIBIT C

                  (STOCK ASSIGNMENT SEPARATE FROM CERTIFICATE)

     FOR VALUE RECEIVED, I hereby sell, assign and transfer unto
__________________ (_________) shares of Common Stock, $0.0001 par value per
share, of BioVex Group, Inc. (the "Corporation") standing in my name on the
books of the Corporation represented by Certificate(s) Number __________
herewith, and do hereby irrevocably constitute and appoint
______________________ attorney to transfer the said stock on the books of the
Corporation with full power of substitution in the premises.

                                         Dated: ____________________

                                         Signature:
                                                    ----------------------------

     NOTICE: The signature(s) to this assignment must correspond with the name
as written upon the face of the certificate, in every particular, without
alteration, enlargement, or any change whatever and must be guaranteed by a
commercial bank, trust company or member firm of the Boston, New York or Midwest
Stock Exchange.

                                      -12-

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