Exhibit 10.8


 


FORM OF SPONSOR LETTER AGREEMENT


 


This SPONSOR LETTER AGREEMENT
(this “Agreement”), dated as of June __, 2021, is entered into as a deed by and among Broadstone Sponsor
LLP, a United Kingdom limited liability partnership (the “Sponsor”), Broadstone Acquisition Corp., a Cayman
Islands exempted company (“Broadstone”), Vertical Aerospace Group Ltd., a company limited by shares incorporated
in England and Wales under registration number 12590994 (the “Company”), Vertical Aerospace Ltd., a Cayman Islands
exempted company incorporated with limited liability (“Pubco”) and Vertical Merger Sub Ltd., a Cayman Islands
exempted company incorporated with limited liability (“Merger Sub”). The Sponsor, Broadstone and the Company
shall be referred to herein from time to time collectively as the “Parties”. Capitalized terms used but not
otherwise defined herein shall have the meanings ascribed to such terms in the Business Combination Agreement (as defined below).


 


WHEREAS, concurrently
with the execution of this Agreement, Broadstone, Pubco, Merger Sub, the Sponsor, the Company and certain other parties thereto are entering
into that certain Business Combination Agreement dated as of the date hereof (as it may be amended, restated or otherwise modified from
time to time in accordance with its terms, the “Business Combination Agreement”), pursuant to which, among other
things, Broadstone will merge with and into Merger Sub (the “Merger”) and Pubco will acquire all of the issued
and outstanding shares of the Company (the “Share Acquisition”);


 


WHEREAS, the Business
Combination Agreement contemplates that the Parties will enter into this Agreement concurrently with the entry into the Business Combination
Agreement by the parties thereto, pursuant to which, among other things, the Sponsor agrees that it will (a) vote in favor of approval
of the Business Combination Agreement, the Ancillary Documents and the transactions contemplated by each of them, including the Shareholder
Approval Matters (b) waive any adjustment to the conversion ratio or any other anti-dilution or similar protection with respect to
the Purchaser Class B Shares set forth in the Organisational Documents of Broadstone and/or, after giving effect to the Merger, the
Pubco Ordinary Shares set forth in the Organisational Documents of Pubco (in each case resulting from the transactions contemplated by
the Business Combination Agreement).


 


NOW, THEREFORE, in
consideration of the premises and the mutual promises contained herein and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the Parties, each intending to be legally bound, hereby agree as follows:


 






    1


     


    

 


1.            Agreement
to Vote.


 


(a)            The
Sponsor hereby irrevocably and unconditionally agrees, at any meeting of the shareholders of Broadstone duly called and convened in accordance
with the Organisational Documents of Broadstone, whether or not adjourned and however called, including at the Special Shareholder Meeting
or otherwise, and in any action by written consent of the shareholders of Broadstone, (i) to vote, or cause to be voted, or execute
and return, or cause to be executed and returned, an action by written consent with respect to, as applicable, all of the Sponsor’s
Purchaser Class B Shares and Purchaser Class A Shares (if any) (the “Sponsor Purchaser Ordinary Shares”),
in each case, held of record or beneficially by Sponsor as of the date of this Agreement, or to which the Sponsor acquires record or beneficial
ownership after the date hereof and prior to the Share Acquisition Closing (the “Closing”) (including by reason
of the Merger) (collectively, the “Subject Equity Securities”) in favor of each of the Shareholder Approval
Matters, in each case, to the extent such Subject Equity Securities are entitled to vote thereon or consent thereto (ii) when such
meeting is held, appear at such meeting or otherwise cause the applicable Subject Equity Securities to be counted as present thereat for
the purpose of establishing a quorum, (iii) to the fullest extent permitted under applicable Law, waive any dissenters, appraisal
or other similar rights, whether such rights are afforded by law or contract, in respect of the transactions contemplated by the Business
Combination Agreement and the Ancillary Documents, including the Merger, (iv) to vote against, or cause to be voted against, or withhold
consent, or cause consent to be withheld, with respect to, any other matter, action or proposal that would reasonably be expected to result
in (x) a breach of any of Broadstone, Pubco or Merger Sub’s (each a “Broadstone Party”) covenants,
agreements or obligations under the Business Combination Agreement or any of the Ancillary Documents or (y) any of the conditions
to the consummate of the Transactions set forth in Articles 10.1 (Condition to Each Party’s Obligations) or 10.3 (Conditions to
Obligations of Purchaser, Pubco and Merger Sub) of the Business Combination Agreement not being satisfied; and (v) not to redeem,
elect to redeem or tender or submit any of its Subject Equity Securities for redemption in connection with the Shareholder Approval Matters,
the Merger, the Share Acquisition or any other transactions contemplated by the Business Combination Agreement. Without limiting the generality
of the foregoing, prior to any valid termination of the Business Combination Agreement, to the extent within its power to do so in its
capacity as holder of Sponsor Purchaser Ordinary Shares, the Sponsor shall take, or cause to be taken, all actions and to do, or cause
to be done, all things reasonably necessary under applicable Laws to consummate the Merger and the other transactions contemplated by
the Business Combination Agreement and on the terms and subject to the conditions set forth therein. The obligations of the Sponsor specified
in this Section 1 shall apply whether or not the Merger, any of the transactions contemplated by the Merger Agreement or any
action described above is recommended by Broadstone’s or the Sponsor’s board of directors.


 


(b)            The
Sponsor irrevocably and unconditionally agrees that, as promptly as reasonably practicable (and in any event within five (5) Business
Days) following the time at which the Registration Statement / Proxy Statement is declared effective under the Securities Act and upon
written notice thereof from the Company or Broadstone, it shall duly execute and deliver to Pubco properly completed and duly executed
stock transfer form(s), in each case with respect to that Subject Equity Securities, or indemnities in respect thereof (the “STFs”),
together with any and all Ancillary Documents required to be executed and delivered by the Sponsor as such are provided for in the Business
Combination Agreement, and any other agreement, instrument or document required by the Company or Broadstone to validate, give effect
to or otherwise implement the Business Combination Agreement and the Transactions (together the “Share Acquisition Documents”).


 


(c)            The
Sponsor hereby agrees, consents to and approves (i) the transactions contemplated by the Business Combination and the Ancillary Documents
and (ii) entry into by the Sponsor the Business Combination Agreement and the Share Acquisition Documents.


 



     


     


    




 


(d)            Without
limiting any other rights or remedies of the Company, in the event that Sponsor fails to perform or otherwise comply with the covenants,
agreements or obligations set forth in Section 1(a) or Section 1(b) hereof (such failure, a “POA
Event”), then, solely in such circumstances and solely to the extent set forth herein, the Sponsor hereby irrevocably appoints
each member of the board of directors of the Company as the Sponsor’s true and lawful representative, agent, attorney and proxy
(with full power of substitution and resubstitution), for and in the name, place and stead of Sponsor (the “Appointment”),
(i) to execute and deliver on its behalf all Share Acquisition Documents, (ii) to attend on behalf of Sponsor any meeting of
Broadstone’s shareholders with respect to the matters described in Section 1(a) or Section 1(b) hereof,
(iii) to include the applicable Subject Equity Securities in any computation for purposes of establishing a quorum at any such meeting
of the holders of Purchaser Ordinary Shares and (iv) to vote (or cause to be voted), or deliver a written consent (or withhold consent),
or waive, revoke or not assert any right, if applicable, with respect to the applicable Subject Equity Securities on the matters specified
in, and in accordance and consistent with Section 1(a) or Section 1(b) hereof in connection with any
meeting of the holders of Purchaser Ordinary Shares or any action by written consent by the holders of Purchaser Ordinary Shares. The
Sponsor hereby revokes any appointment previously granted by it with respect to the Subject Equity Securities, if any. Notwithstanding
anything contained herein to the contrary, this Appointment shall automatically terminate upon the earlier of the termination of the Business
Combination Agreement in accordance with its terms or the Share Acquisition Closing.


 


(e)            The
Appointment granted by the Sponsor is granted in consideration for the Company and Broadstone entering into the Business Combination Agreement
and agreeing to consummate the transactions contemplated thereby. The Appointment granted by the Sponsor is unconditional and irrevocable
and shall survive the bankruptcy, dissolution, death, incapacity or other inability to act by the Sponsor. The Appointment may only be
exercised with respect to the matters described in Section 1(a) or Section 1(b). Upon the occurrence of a
POA Event, the Sponsor hereby approves, authorizes and ratifies everything which any member of the board of directors of the Company shall
lawfully due pursuant to this Section 1 to the extent consistent with the terms and conditions of this Agreement, the Business
Combination Agreement and the Share Acquisition Documents.


 


2.            Waiver
of Anti-dilution Protection. Subject to, and conditioned upon, the occurrence of the Closing, to the fullest extent permitted by law,
the Sponsor (on behalf of itself and for its successors, heirs and assigns) hereby waives, and agrees not to assert or perfect, any rights
to adjustment or other anti-dilution protections with respect to the rate that the Purchaser Class B Shares held by it convert into
Purchaser Class A Shares, as set out in Article 17.3 of the Amended and Restated Memorandum and Articles of Association of Broadstone
(or Pubco Ordinary Shares), in connection with the transactions contemplated by the Business Combination Agreement and the Ancillary Documents,
provided always that this Section 2 shall not apply to the extent that any such waiver by the Sponsor will result in the Purchaser
Class B Shares converting into Purchaser Class A Shares (or Pubco Ordinary Shares) on anything less than a one-for-one basis.


 






     


     


    

 


3.            Transfer
of Shares.


 


(a)            Except
as expressly contemplated by the Business Combination Agreement (including in connection with the Merger) or with the prior written consent
of the Company (such consent to be given or withheld in its sole discretion), from and after the date hereof until the effective date
of the termination of this Agreement in accordance with Section 7, the Sponsor hereby agrees that it shall not (i) Transfer
any of its Subject Equity Securities, (ii) enter into (A) any option, warrant, purchase right, or other Contract that could
(either alone or in connection with one or more events, developments or events (including the satisfaction or waiver of any conditions
precedent)) require the Sponsor to Transfer its Subject Equity Securities or (B) any voting trust, proxy or other Contract with respect
to the voting or Transfer of the Subject Equity Securities, or (iii) enter into any Contract to take, or cause to be taken, any of
the actions set forth in clauses (i) or (ii); provided, however, that the foregoing shall not apply to
any Transfer (1) to Broadstone’s officers or directors, any members or partners of the Sponsor, any Affiliates of the Sponsor,
or any employees of such Affiliate; (2) in the case of an individual, by gift to a member of one of the individual’s immediate
family, to a trust, the beneficiary of which is a member of the individual’s immediate family or an Affiliate of such individual
or to a charitable organization; (3) in the case of an individual, by virtue of laws of descent and distribution upon death of the
individual; (4) in the case of an individual, pursuant to a qualified domestic relations order; or (5) by virtue of the Sponsor’s
Organizational Documents upon liquidation or dissolution of the Sponsor; provided, that the Sponsor shall, and shall cause any
transferee of its Subject Equity Securities of the type set forth in clauses (1) through (5), to enter into a written agreement in
form and substance reasonably satisfactory to the Company, agreeing to be bound by this Agreement prior to the occurrence of such Transfer.
For purposes of this Agreement, “Transfer” means any, direct or indirect, sale, transfer, assignment, pledge,
mortgage, exchange, hypothecation, grant of a security interest or encumbrance in or disposition of an interest (whether with or without
consideration, whether voluntarily or involuntarily or by operation of law or otherwise).


 


(b)            In
furtherance of the foregoing, to the extent that the Sponsor holds Subject Equity Securities that are listed on NYSE the Sponsor hereby
agrees to (i) place a revocable stop order on all such Subject Equity Securities subject to Section 3(a), including
those which may be covered by a registration statement, and (ii) notify Broadstone’s transfer agent in writing of such stop
order and the restrictions on such Subject Equity Securities under Section 3(a) and direct Broadstone’s transfer
agent not to process any attempts by the Sponsor to Transfer any Subject Equity Securities except in compliance with Section 3(a);
for the avoidance of doubt, the obligations of the Sponsor under this Section 3(a) shall be deemed to be satisfied
by the existence of any similar stop order and restrictions currently existing on the Subject Equity Securities.


 


(c)            The
transfer restrictions provided for in section 7 of the letter agreement entered into between, inter alia, the Sponsor and Broadstone,
dated September, 10, 2020 (the “Insider Letter Agreement”), shall not apply to any transfer of Purchaser Class B
Shares or Purchaser Private Warrants by the Sponsor pursuant to the terms of the Business Combination Agreement. Furthermore, at Share
Acquisition Closing, the Transfer Restriction (as such term is defined in the Lock-Up Agreement for the Sponsor) shall replace and supersede
in its entirety the transfer restriction imposed on the Sponsor and the Insiders (as such term is defined in the Insider Letter Agreement)
pursuant to section 7 of the Insider Letter Agreement.


 






     


     


    

 


4.            Release
of Claims. In consideration for the benefits to be received by the Sponsor under the terms of the Business Combination Agreement and
the Ancillary Documents, subject to and effective as of the Closing, the Sponsor, for and on behalf of itself and each of its heirs, executors,
administrators, personal representatives, successors, assigns and subsidiaries, hereby acknowledges full and complete satisfaction of
and fully and irrevocably releases and forever discharges the Company, Broadstone, the Target Companies, Pubco, Merger Sub, each of their
respective subsidiaries and their predecessors, successors, assignees, parent companies, shareholders and investors (direct and indirect)
and, in each case, each of their respective Affiliates, officers, directors, partners, employees, agents, attorneys and other representatives,
past and present (collectively, the “Released Entities”), from liability on or for any and all charges, claims,
controversies, actions, causes of action, cross claims, counterclaims, demands, debts, duties, sanctions, fines, compensatory damages,
liquidated damages, punitive or exemplary damages, other damages, claims for costs, attorney’s fees, sums of money, suits, contracts,
covenants, controversies, agreements, promises, responsibilities, obligations and accounts of any kind, nature or description whatsoever
in Law or in equity (“Actions”), direct or indirect, past, present and future, and whether or not now or heretofore
known, suspected, matured or unmatured, contingent or uncontingent, or claimed against the Released Entities, through to and including
the Closing, arising out of, or relating to, (x) the Sponsor’s ownership of any Sponsor Purchaser Ordinary Shares or any equity
or debt interests in Broadstone prior to the Closing, (y) the organization, management or operation of the business of Broadstone
relating to any matter, occurrence, action, inaction, omission or activity prior to the Closing, in each case, in the Sponsor’s
capacity as an equity or debt securityholder, and (z) the negotiation, implementation or closing of the transactions contemplated
by the Business Combination Agreement; provided, that such release shall not release the Released Entities for (i) any Actions
arising out of or related to the Released Entities’ respective Organisational Documents, to provide indemnification, reimbursement
or advancement of expenses to the Sponsor in respect of actions taken or omitted in the Sponsor’s capacity as an officer and/or
director of such Released Entity prior to the Closing, (ii) any Actions arising out of or related to the Released Entities’
contracts with or obligations to the Sponsor in respect of compensation arrangements as an officer and/or director of such Released Entity
prior to the Closing, (iii) any Actions arising under, or in connection with, any commercial agreements as between any direct or
indirect portfolio companies of the Sponsor or its Affiliates and any Released Entity, or (iv) for the avoidance of doubt, any Actions
arising in Sponsor’s capacity as a member of Pubco under its Organisational Documents (if applicable), the New Registration Rights
Agreement, in each case, arising after the Closing.


 


5.            Other
Covenants.


 


(a)            The
Sponsor hereby agrees that it shall be bound by and subject to Sections 8.14 (Public Announcements) and 8.15 (Confidential Information)
of the Business Combination Agreement to the same extent as such provisions apply to the parties to the Business Combination Agreement.


 


(b)            The
Sponsor hereby covenants and agrees that it shall not, at any time prior to termination of this Agreement, (i) enter into any voting
agreement or voting trust with respect to any Subject Equity Securities that is inconsistent with the Sponsor’s obligations pursuant
to this Agreement, (ii) grant a proxy or power of attorney with respect to any of the Sponsor’s Subject Equity Securities that
is inconsistent with the Sponsor’s obligations pursuant to this Agreement, or (iii) enter into any agreement or undertaking
that is otherwise inconsistent with, or would interfere with, or prohibit or prevent the Sponsor from satisfying, its obligations pursuant
to this Agreement.


 






     


     


    

 


(c)            The
Sponsor acknowledges and agrees that the Company is entering into the Business Combination Agreement in reliance upon the Sponsor entering
into this Agreement and agreeing to be bound by, and perform, or otherwise comply with, as applicable, the agreements, covenants and obligations
contained in this Agreement and but for the Sponsor entering into this Agreement and agreeing to be bound by, and perform, or otherwise
comply with, as applicable, the agreements, covenants and obligations contained in this Agreement, the Company would not be entering into
or agreeing to consummate the transactions contemplated by the Business Combination Agreement or the Ancillary Documents.


 


6.            Representations
and Warranties. The Sponsor represents and warrants to the Company as follows:


 


(a)            The
Sponsor is duly formed, validly existing and in good standing under the Laws of its jurisdiction of formation.


 


(b)            The
Sponsor has the requisite limited liability company power and authority to execute and deliver this Agreement, to perform its covenants,
agreements and obligations hereunder (including, for the avoidance of doubt, those covenants, agreements and obligations hereunder that
relate to the provisions of the Business Combination Agreement), and to consummate the transactions contemplated hereby. The execution
and delivery of this Agreement has been duly authorized by all necessary action on the part of the Sponsor. This Agreement has been duly
and validly executed and delivered by the Sponsor and constitutes a valid, legal and binding agreement of the Sponsor (assuming that this
Agreement is duly authorized, executed and delivered by the other Parties hereto), enforceable against the Sponsor in accordance with
its terms (subject to applicable bankruptcy, insolvency, reorganization, moratorium or other Laws affecting generally the enforcement
of creditors’ rights and subject to general principles of equity).


 


(c)            No
consent, approval or authorization of, or designation, declaration or filing with, any Governmental Authority is required on the part
of the Sponsor with respect to the Sponsor’s execution, delivery or performance of its covenants, agreements or obligations under
this Agreement (including, for the avoidance of doubt, those covenants, agreements and obligations under this Agreement that relate to
the provisions of the Business Combination Agreement) or the consummation of the transactions contemplated hereby, except for any consents,
approvals, authorizations, designations, declarations, waivers or filings, the absence of which would not adversely affect the ability
of the Sponsor to perform, or otherwise comply with, any of its covenants, agreements or obligations hereunder in any material respect.


 


(d)            None
of the execution or delivery of this Agreement by the Sponsor, the performance by the Sponsor of any of its covenants, agreements or obligations
under this Agreement (including, for the avoidance of doubt, those covenants, agreements and obligations under this Agreement that relate
to the provisions of the Business Combination Agreement) or the consummation of the transactions contemplated hereby will, directly or
indirectly (with or without due notice or lapse of time or both) (i) result in any breach of any provision of the Sponsor’s
Organisational Documents, (ii) result in a violation or breach of, or constitute a default or give rise to any right of termination,
Consent, cancellation, amendment, modification, suspension, revocation or acceleration under, any of the terms, conditions or provisions
of any Contract to which the Sponsor is a party, (iii) violate, or constitute a breach under, any Order or applicable Law to which
the Sponsor or any of its properties or assets are bound or (iv) result in the creation of any Lien upon the Subject Equity Securities,
except, in the case of any of clauses (ii) through (iv) above, as would not adversely affect the ability of the Sponsor to perform,
or otherwise comply with, any of its covenants, agreements or obligations under this Agreement in any material respect.


 



     


     


    

 


(e)            The
Sponsor is the record and beneficial owner of the Sponsor Purchaser Ordinary Shares and has valid, good and marketable title to the Sponsor
Purchaser Ordinary Shares (and, following the consummation of the Merger, the Pubco Ordinary Shares received by the Sponsor in exchange
for the Sponsor Purchaser Ordinary Shares (the “Sponsor Pubco Shares”)), free and clear of all Liens (other
than transfer restrictions under the Securities Act, under the Organisational Documents of Broadstone (or, following the Merger the Organisational
Documents of Pubco), or as set forth in the Broadstone Disclosure Schedules). Except for the Equity Securities of Broadstone set forth
on Schedule I hereto, together with any other Equity Securities of Broadstone and/or Pubco that the Sponsor acquires record or
beneficial ownership of after the date hereof that is either permitted pursuant to, or acquired in accordance with, the Business Combination
Agreement (including in connection with the Merger), the Sponsor does not own, beneficially or of record, any Equity Securities of Broadstone
or Pubco or have the right to acquire any Equity Securities of Broadstone or Pubco. The Sponsor has the sole right to vote (and provide
consent in respect of, as applicable) the Sponsor Purchaser Ordinary Shares (and following the Merger the Sponsor Pubco Shares) and, except
for this Agreement, the Business Combination Agreement, the Organisational Documents of Broadstone, the Organisational Documents of Pubco
or any proxy given for purposes of voting in favor of the Shareholder Approval Matters, the Sponsor is not party to or bound by (i) any
option, warrant, purchase right, or other Contract that could (either alone or in connection with one or more events, developments or
events (including the satisfaction or waiver of any conditions precedent)) requiring the Sponsor to Transfer any of the Sponsor Purchaser
Ordinary Shares (or, following the Merger the Sponsor Pubco Shares) or (ii) any voting trust, proxy or other Contract with respect
to the voting or Transfer of any of the Sponsor Purchaser Ordinary Shares (or, following the Merger the Sponsor Pubco Shares) in a manner
inconsistent with the requirements of this Agreement. The Sponsor holds 100% of the issued and outstanding Purchaser Class B Shares
as of the date hereof.


 


(f)            There
is no Action pending or, to the Sponsor’s knowledge, threatened against or involving the Sponsor or any of its Affiliates that,
if adversely decided or resolved, would reasonably be expected to adversely affect the ability of the Sponsor to perform, or otherwise
comply with, any of its covenants, agreements or obligations under this Agreement in any material respect.


 


(g)            The
Sponsor, on its own behalf and on behalf of its Representatives, acknowledges, represents, warrants and agrees that (i) it has conducted
its own independent review and analysis of, and, based thereon, has formed an independent judgment concerning, the business, assets, condition,
operations and prospects of, the Company and the transactions contemplated by this Agreement, the Business Combination Agreement and the
other Ancillary Documents to which it is or will be a party and (ii) it has been furnished with or given access to such documents
and information about the Company and their respective businesses and operations as it and its Representatives have deemed necessary to
enable him, her or it to make an informed decision with respect to the execution, delivery and performance of this Agreement or the other
Ancillary Documents to which it is or will be a party and the transactions contemplated hereby and thereby.


 






     


     


    

 


(h)            In
entering into this Agreement and the other Ancillary Documents to which he, she or it is or will be a party, the Sponsor has relied solely
on its own investigation and analysis and the representations and warranties expressly set forth in the Ancillary Documents to which it
is or will be a party and no other representations or warranties of any of the Target Companies (including, for the avoidance of doubt,
none of the representations or warranties of the Company set forth in the Business Combination Agreement or any other Ancillary Document
to which the Sponsor is not and will not be a party) or any other Person, either express or implied, and the Sponsor, on its own behalf
and on behalf of its Representatives, acknowledges, represents, warrants and agrees that, except for the representations and warranties
expressly set forth in this Agreement or in the other Ancillary Documents to which he, she or it is or will be a party, none of the Target
Companies or any other Person makes or has made any representation or warranty, either express or implied, in connection with or related
to this Agreement, the Business Combination Agreement or the other Ancillary Documents or the transactions contemplated hereby or thereby.


 


7.            Termination.
This Agreement shall automatically terminate, without any notice or other action by any Party, and be void ab initio upon the termination
of the Business Combination Agreement in accordance with its terms. Upon termination of this Agreement as provided in the immediately
preceding sentence, none of the Parties shall have any further obligations or Liabilities under, or with respect to, this Agreement. Notwithstanding
the foregoing or anything to the contrary in this Agreement, (i) Section 4 shall survive any termination of this Agreement,
(ii) the termination of this Agreement shall not affect any Liability on the part of any Party for a willful and material breach
of any covenant or agreement set forth in this Agreement prior to such termination or actual fraud, and (iii) Section 5(a) (solely
to the extent that it relates to Section 8.15 (Confidential Information) of the Business Combination Agreement), Section 19,
and Section 20 shall each survive any termination of this Agreement.


 


8.            No
Recourse. Except for claims pursuant to the Business Combination Agreement or any other Ancillary Document by any party(ies) thereto
against any other party(ies) thereto on the terms and subject to the conditions therein, each Party agrees that (a) this Agreement
may only be enforced against, and any action for breach of this Agreement may only be made against, the Parties, and no claims of any
nature whatsoever (whether in tort, contract or otherwise) arising under or relating to this Agreement, the negotiation hereof or its
subject matter, or the transactions contemplated hereby shall be asserted against any Representatives of any Party (other than the Persons
named as parties hereto), and (b) none of the Representatives of any Party (other than the Persons named as parties hereto, on the
terms and subject to the conditions set forth herein) shall have any Liability arising out of or relating to this Agreement, the negotiation
hereof or its subject matter, or the transactions contemplated hereby, including with respect to any claim (whether in tort, contract
or otherwise) for breach of this Agreement or in respect of any written or oral representations made or alleged to be made in connection
herewith, or for any actual or alleged inaccuracies, misstatements or omissions with respect to any information or materials of any kind
furnished in connection with this Agreement, the negotiation hereof or the transactions contemplated hereby. Notwithstanding anything
to the contrary in this Agreement, in no event shall Broadstone have any obligations or Liabilities related to or arising out of the covenants,
agreements, obligations, representations or warrants of the Sponsor under this Agreement (including related to or arising out of any breach
of any such covenant, agreement, obligation, representation or warranty by the Sponsor).


 






     


     


    

 


9.              Further
Assurances. From time to time, at the request of the Company, Pubco or Merger Sub, the Sponsor shall execute and deliver such additional
documents and take all such further action as may be reasonably necessary or reasonably requested to effect the actions and consummate
the transactions contemplated by this Agreement. The Sponsor further agrees not to commence or participate in, and to take all actions
necessary to opt out of any class action with respect to, any action or claim, derivative or otherwise, against the Company, any Affiliate
of the Company, Pubco, Merger Sub, or any of their respective successors and assigns challenging the transactions contemplated by the
Business Combination Agreement, including the Share Acquisition.


 


10.            Fiduciary
Duties. Notwithstanding anything in this Agreement to the contrary, (a) the Sponsor makes no agreement or understanding herein
in any capacity other than in the Sponsor’s capacity as a record holder and/or beneficial owner of the Subject Equity Securities,
and (b) nothing herein will be construed to limit or affect any action or inaction by any representative of the Sponsor serving as
a member of the board of directors (or other similar governing body) of any Broadstone Party or as an officer, employee or fiduciary of
a Broadstone Party, in each case, acting in such person’s capacity as a director, officer, employee or fiduciary of such Broadstone
Party.


 


11.            Disclosure.
The Sponsor hereby authorizes each of Broadstone, the Company, Pubco and Merger Sub to publish and disclose in any announcement or disclosure
required by the SEC the Sponsor’s identity and ownership of the Subject Equity Securities and the nature of the Sponsor’s
obligations under this Agreement.


 


12.            Changes
in Capital Stock. In the event of a stock split, stock dividend or distribution, or any change in Broadstone’s capital stock
by reason of any split-up, reverse stock split, recapitalisation, combination, reclassification, exchange of shares or the like, the term
 “Subject Equity Securities” shall be deemed to refer to and include such shares as well as all such stock dividends and distributions
and any securities into which or for which any or all of such shares may be changed or exchanged or which are received in such transaction.


 


13.            No
Third Party Beneficiaries. This Agreement shall be for the sole benefit of the Parties and their respective successors and permitted
assigns (which shall, for the avoidance of doubt, include any successor to Broadstone, including Pubco, which successor shall be bound
by all obligations and entitled to enforce all rights of Broadstone under this Agreement) and is not intended, nor shall be construed,
to give any Person, other than the Parties and their respective successors and assigns, any legal or equitable right, benefit or remedy
of any nature whatsoever by reason this Agreement; provided, however, that each of the Released Entities shall be express
third-party beneficiaries of Section 4; each Target Company shall be an express third-party beneficiary of Section 6(h) and
each Insider shall be an express third-party beneficiary of Section 3(c). Nothing in this Agreement, expressed or implied,
is intended to or shall constitute the Parties, partners or participants in a joint venture.


 






     


     


    

 


14.            Notices.
All notices, requests, claims, demands and other communications hereunder shall be in writing and shall be given (and shall be deemed
to have been duly given) by delivery in person, by e-mail (having obtained electronic delivery confirmation thereof (i.e., an electronic
record of the sender that the email was sent to the intended recipient thereof without an “error” or similar message that
such email was not received by such intended recipient)), or by registered or certified mail (postage prepaid, return receipt requested)
(upon receipt thereof) to the other Parties as follows:


 


If to the Sponsor, to:


 


Broadstone Sponsor LLP

7 Portman Mews South, Marylebone, London W1H 6AY, United Kingdom

Attn: Edward Hawkes and Marc Jonas

Email: ######@#####.### and ######@#####.###


 


with a copy to (prior to the
Closing) (which will not constitute notice):


 


Winston & Strawn London LLP


CityPoint, One Ropemaker Street, London EC2Y 9AW, United
Kingdom


Attn: Paul Amiss and Nicholas Usher


Email: ######@#####.### and ######@#####.###


 


If to Broadstone, to:


 


Broadstone Acquisition Corp.

7 Portman Mews South, Marylebone, London W1H 6AY, United Kingdom

Attn: Edward Hawkes and Marc Jonas

Email: ######@#####.### and ######@#####.###


 


with a copy to (prior to the Closing) (which will not constitute
notice):


 


Winston & Strawn London LLP


CityPoint, One Ropemaker Street, London EC2Y 9AW, United
Kingdom


Attn: Paul Amiss and Nicholas Usher


Email: ######@#####.### and ######@#####.###


 


If to the Company, to:


 


Vertical Aerospace Group Ltd.

140-142 Kensington Church Street, London, W8 4BN, United Kingdom

Email: ######@#####.###


 


with a copy (which shall not constitute notice)
to:


 


Latham & Watkins (London) LLP


99 Bishopsgate, London, EC2M 3XF, United Kingdom


Attn: David Stewart and Robbie McLaren 


Email: ######@#####.### and ######@#####.###


 






     


     


    

 


or to such other address as the Party to whom notice is given may have
previously furnished to the others in writing in the manner set forth above.


 


15.            Amendment
and Modification. This Agreement may not be amended, modified or supplemented in any manner, whether by course of conduct or otherwise,
except by an instrument in writing signed by the Parties.


 


16.            Waiver.
No failure or delay by any Party hereto exercising any right, power or privilege hereunder shall operate as a waiver thereof nor shall
any single or partial exercise thereof preclude any other or further exercise thereof or the exercise of any other right, power or privilege.
The rights and remedies of the parties hereto hereunder are cumulative and are not exclusive of any rights or remedies which they would
otherwise have hereunder. Any agreement on the part of a Party hereto to any such waiver shall be valid only if set forth in a written
instrument executed and delivered by such Party.


 


17.            Entire
Agreement. This Agreement, the Business Combination Agreement and the other Ancillary Documents constitute the entire agreement of
the Parties with respect to the subject matter of this Agreement, and supersedes all prior agreements and understandings, both written
and oral, among the Parties with respect to the subject matter hereof.


 


18.            Assignment;
Successors. Neither this Agreement nor any of the rights, interests or obligations hereunder shall be assigned by any of the Parties
hereto in whole or in part (whether by operation of Law or otherwise) without the prior written consent of the other Parties, and any
such assignment without such consent shall be null and void. This Agreement shall be binding upon, inure to the benefit of and be enforceable
by the Parties hereto and their respective successors and permitted assigns.


 


19.            Fees
and Expenses. Except as otherwise set forth in the Business Combination Agreement, all fees and expenses incurred in connection with
this Agreement and the transactions contemplated hereby, including the fees and disbursements of counsel, financial advisors and accountants,
shall be paid by the Party incurring such fees or expenses; provided, that, any such fees and expenses incurred by the Sponsor
shall be deemed to be Purchaser Transaction Expenses.


 


20.            No
Ownership Interest. Nothing contained in this Agreement will be deemed to vest in the Company any direct or indirect ownership or
incidents of ownership of or with respect to the Subject Equity Securities. All rights, ownership and economic benefits of and relating
to the Subject Equity Securities shall remain vested in and belong to the Sponsor, and the Company shall have no authority to manage,
direct, superintend, restrict, regulate, govern or administer any of the policies or operations of any Broadstone Party or exercise any
power or authority to direct the Sponsor in the voting of any of the Subject Equity Securities, except as otherwise expressly provided
herein with respect to the Subject Equity Securities. Except as otherwise expressly provided in Section 1, the Sponsor shall
not be restricted from voting in favor of, against or abstaining with respect to or giving (or withholding) its written consent to any
other matters presented to the shareholders of Broadstone (or any successor thereto).


 






     


     


    

 


21.            Non-Survival.
The representations and warranties, and each of the agreements and covenants (to the extent such agreement or covenants contemplates or
requires performance at or prior to the Closing) in this Agreement shall terminate at the Closing, and each covenant and agreement contained
herein that by its terms, expressly contemplates performance after the Closing shall so survive the Closing in accordance with its terms,
in each case, subject to Section 7; provided, however, notwithstanding the foregoing the Liability on the part of any Party
for a willful and material breach of any covenant or agreement set forth in this Agreement prior to Closing or actual fraud shall not
be affected.


 


22.            Specific
Performance. Each Party acknowledges that the rights of each Party to consummate the Transactions are unique, recognises and affirms
that in the event of a breach of this Agreement by any Party, money damages may be inadequate and the non-breaching Parties may have not
adequate remedy at law, and agree that irreparable damage may occur in the event that any of the provisions of this Agreement were not
performed by an applicable Party in accordance with their specific terms or were otherwise breached. Accordingly, each Party shall be
entitled to seek an injunction, specific performance or other equitable remedy to prevent or remedy any breach of this Agreement and to
seek to enforce specifically the terms and provisions hereof, in each case, without the requirement to post any bond or other security
or to prove that money damages would be inadequate, this being in addition to any other right or remedy to which such Party may be entitled
under this Agreement, at law or in equity.


 


23.            Severability.
If any term or other provision of this Agreement is held by a court of competent jurisdiction or other authority to be invalid, void,
unenforceable or against its regulatory policy, the remainder of the terms and provisions of this Agreement shall remain in full force
and effect and shall in no way be affected, impaired or invalidated, so long as the economic and legal substance of the transactions contemplated
hereby, taken as a whole, are not affected in a manner materially adverse to any party hereto. Upon such a determination, the parties
hereto shall negotiate in good faith to modify this Agreement so as to effect the original intent of the parties hereto as closely as
possible in an acceptable manner in order that the transactions contemplated hereby be consummated as originally contemplated to the fullest
extent possible.


 


24.            Counterparts.
This Agreement may be executed in one or more counterparts, all of which shall be considered one and the same agreement, it being understood
that each party need not sign the same counterpart. This Agreement shall become effective when each party shall have received a counterpart
hereof signed by all of the other parties. Signatures delivered electronically or by facsimile shall be deemed to be original signatures.


 


25.            Governing
Law; Jurisdiction. This Agreement and any non-contractual rights or obligations arising out of or in connection with it shall be governed
by and construed in accordance with the laws of England and Wales. The parties irrevocably agree that the courts of England and Wales
shall have exclusive jurisdiction to hear, determine and settle any Disputes and, for such purposes, irrevocably submit to the jurisdiction
of such courts, and waive any objection to proceedings before such courts on the grounds of venue or on the grounds that such proceedings
have been brought in an inappropriate forum. For the purposes of this Section 25, “Dispute” means
any dispute, controversy, claim or difference of whatever nature arising out of, relating to, or having any connection with this Agreement,
including a dispute regarding the existence, formation, validity, interpretation, performance or termination of this Agreement or the
consequences of its nullity and also including any dispute relating to any non-contractual rights or obligations arising out of, relating
to, or having any connection with this Agreement.


 






     


     


    

 


26.            Interpretation
and Construction. The words “hereof,” “herein” and “hereunder” and words of like import used in
this Agreement shall refer to this Agreement as a whole and not to any particular provision of this Agreement. The descriptive headings
used herein are inserted for convenience of reference only and are not intended to be part of or to affect the meaning or interpretation
of this Agreement. References to Sections are to Sections of this Agreement unless otherwise specified. Any singular term in this Agreement
shall be deemed to include the plural, and any plural term the singular. The definitions contained in this Agreement are applicable to
the masculine as well as to the feminine and neuter genders of such term. Whenever the words “include,” “includes”
or “including” are used in this Agreement, they shall be deemed to be followed by the words “without limitation,”
whether or not they are in fact followed by those words or words of like import. “Writing,” “written” and comparable
terms refer to printing, typing and other means of reproducing words (including electronic media) in a visible form. References to any
statute shall be deemed to refer to such statute and to any rules or regulations promulgated thereunder. References to any person
include the successors and permitted assigns of that person. References from or through any date mean, unless otherwise specified, from
and including such date or through and including such date, respectively. In the event an ambiguity or question of intent or interpretation
arises, this Agreement will be construed as if drafted jointly by the Parties, and no presumption or burden of proof will arise favoring
or disfavoring any Party by virtue of the authorship of any of the provisions of this Agreement.


 


IN WITNESS WHEREOF, the parties hereto have caused
this Agreement to be executed as a DEED as of the date first written above.


 


[signature page follows]


 






     


     


    

 


SCHEDULE I


 


Equity Securities of Broadstone as of the date
hereof


 


	Shareholder	 	Number of Purchaser Class A Shares	 	 	Number of Purchaser Class B Shares	 	 	Number of Purchaser Public Warrants	 	 	Number of Purchaser Private Warrants	 
	Broadstone Sponsor LLP	 	 	0	 	 	 	7,632,575	 	 	 	0	 	 	 	8,106,060	 



 






     


     


    

 


IN WITNESS WHEREOF, the parties hereto have caused
this Agreement to be executed as a DEED as of the date first written above.


 


	Executed as a Deed by	)	 
	BROADSTONE SPONSOR LLP., acting by	)	 
	_____________________,,	)	 
	a director, and	)	 
	_____________________, a director	)	 
	 	)	 
	 	)	 



 


[Signature
Page to Sponsor Letter Agreement]


 






     


     


    

 


	Executed as a Deed by	)	 
	BROADSTONE ACQUISITION CORP., acting by	)	 
	_____________________,,	)	 
	a director, and	)	 
	_____________________, a director	)	 
	 	)	 
	 	)	 


 


[Signature
Page to Sponsor Letter Agreement]


 






     


     


    

 





	Executed as a Deed by	)	 
	VERTICAL AEROSPACE LTD., acting by	)	 
	_____________________,,	)	 
	a director, and	)	 
	_____________________, a director	)	 
	 	)	 
	 	)	 


 


[Signature
Page to Sponsor Letter Agreement]


 






     


     


    




 





	Executed as a Deed by	)	 
	VERTICAL AEROSPACE GROUP LTD., acting by	)	 
	_____________________,,	)	 
	a director, and	)	 
	_____________________, a director	)	 
	 	)	 
	 	)	 


 


[Signature
Page to Sponsor Letter Agreement]


 






     


     


    

 





	Executed as a Deed by	)	 
	VERTICAL MERGER SUB LTD., acting by	)	 
	_____________________,,	)	 
	a director, and	)	 
	_____________________, a director	)	 
	 	)	 
	 	)	 


 


[Signature
Page to Sponsor Letter Agreement]