Silence Announces Proposed Cancellation of Admission of its Ordinary Shares to Trading on AIM and Transition of its Primary Trading Venue to the Nasdaq Global Market Notice of General Meeting to be held on 1 November 202

Silence Announces Proposed Cancellation of Admission of its Ordinary Shares to Trading on AIM and

Transition of its Primary Trading Venue to the Nasdaq Global Market

Notice of General Meeting to be held on 1 November 2021

LONDON, Silence Therapeutics plc,

AIM:SLN and Nasdaq:SLN ( Silence or the Company ), a leader in the discovery, development and delivery of novel short interfering ribonucleic acid (siRNA) therapeutics for the treatment of diseases with

significant unmet medical need, today announces:

The Proposed AIM Delisting

and the General Meeting

Mark Rothera, President and Chief Executive Officer of Silence Therapeutics, said: This marks a

very important step in the evolution of our company and positions Silence as a global RNAi leader. With our mRNAi GOLD platform advancing in the clinic, we see substantial opportunity to

build value over the next 12 months and longer term. We are grateful to have the continued support of our loyal shareholders and look forward to this exciting new chapter of growth.

Craig Tooman, Chief Financial Officer of Silence Therapeutics, said: A key priority for us has been to create a more attractive and efficient

trading mechanism for our shareholders and to support increasing interest from new investors. We believe the move to trade exclusively on the Nasdaq a top global exchange accomplishes that objective. This is an exciting time for

Silence and we look forward to continuing to expand our global shareholder base.

The Company will today be posting the Circular to shareholders

which will set out further information on the process to deposit Ordinary Shares for delivery of ADSs, including personalised forms for those holders of certificated Ordinary Shares who wish to deposit their Ordinary Shares for delivery of ADSs, as

well as containing the notice of General Meeting. Copies will also be available on Silence s website at www.silence-therapeutics.com.

Background to the AIM Delisting

incorporated in 1994 and its Ordinary Shares have been admitted to trading on AIM since 1995. In September 2020, the Company undertook a direct listing of ADSs representing its Ordinary Shares on the Nasdaq Capital Market. In February 2021, the

Company announced an oversubscribed private placement of ADSs for gross proceeds of approximately $45 million. In June 2021, the Company moved its Nasdaq listing from the Nasdaq Capital Market tier to the Nasdaq Global Market tier.

As at 13 October 2021, being the last practicable date prior to the date of this announcement, approximately 8.9 per cent. of the Company s

Ordinary Shares are represented by ADSs tradeable on Nasdaq. All shareholders who have not already deposited their Ordinary Shares for delivery of ADSs are currently able to do so at any time. Affiliates of the Company who deposit their ordinary

shares may be subject to limitations on resale of ADSs under U.S. securities law. The Company intends to convert an existing secondary resale shelf registration statement on Form F-1 to a short-form

registration statement on Form F-3, which will, upon effectiveness, continue to grant such affiliates the ability to freely resell such restricted securities without restriction.

The AIM Rules for Companies published by London Stock Exchange plc (the London Stock Exchange ) (the AIM Rules for

Companies ) require that, unless the London Stock Exchange otherwise agrees, the cancellation of a company s shares from trading on AIM requires the consent of not less than 75 per cent. of votes cast by its shareholders given in

a general meeting. Notwithstanding that the Company may be able to seek the agreement of the London Stock Exchange that shareholder consent in general meeting is not required due to the listing of ADSs on Nasdaq, the Board has determined to seek

shareholder approval for the proposed AIM Delisting.

Reasons for the AIM Delisting

The Board has decided to implement the AIM Delisting for the following reasons:

Accordingly, the Directors believe that it is no longer in the best interests of the Company or its shareholders as a whole for the Company to retain

admission of its Ordinary Shares to trading on AIM. However, the Company is providing an opportunity for shareholders to deposit their Ordinary Shares with the Company s ADS depositary in exchange for delivery of ADSs, without cost, in

connection with the AIM Delisting whether prior, on, or subsequent to 30 November 2021 (being the date on which the AIM Delisting takes effect), except that the Depositary has not agreed to waive that fee with respect to more than 81,831,467

Ordinary Shares, which is the number of Ordinary Shares that were in issue but not represented by ADSs on 15 October 2021 and has not agreed to waive fees on any deposit made by the Company.

Effect of the AIM Delisting

If the resolutions are

passed at the General Meeting, Shareholders will no longer be able to buy and sell Ordinary Shares on AIM after 29 November 2021. Holders of Ordinary Shares should read Information for holders of Ordinary Shares below which

explains in more detail the process of depositing Ordinary Shares for delivery of ADSs.

As a company incorporated in England and Wales, the Company will

continue to be subject to the requirements of the Companies Act 2006.

Following the AIM Delisting taking effect, the Company will no longer be subject to

the AIM Rules for Companies or be required to retain the services of an independent nominated adviser. The Company will also no longer be subject to the QCA Corporate Governance Code or be required to comply with the continuing obligations set out

in the Disclosure Guidance and Transparency Rules (the DTRs ) of the Financial Conduct Authority (the FCA ) or, provided the Company s securities remain outside the scope of the regulation, UK MAR. In

addition, the Company and its shareholders will no longer be subject to the provisions of the DTRs relating to the disclosure of changes in significant shareholdings in the Company. The Company intends to continue to comply with all regulatory

requirements for the Nasdaq listing of ADSs, including all applicable rules and regulations of the SEC.

Shareholders who continue to hold Ordinary Shares

following the AIM Delisting will continue to be notified of the availability of key documents on the Company s website, including publication of annual reports and annual general meeting documentation. Holders of ADSs will be able to continue

to access all such information via the Silence website. Holders of Ordinary Shares and ADSs will remain entitled to receive any future dividends that may be declared thereon, which dividends will also accrue to ADS holders in accordance with the

terms of the Deposit Agreement.

Application of the City Code following the AIM Delisting

Following the AIM Delisting, as the Company will remain a public limited company incorporated in England and Wales but its securities will not be admitted to

trading on a regulated market or multilateral trading facility in the United Kingdom (or a stock exchange in the Channel Islands or the Isle of Man), the City Code on Takeovers and Mergers (the City Code ) will only apply to the

Company if it is considered by the Panel on Takeovers and Mergers (the Panel ) to have its place of central management and control in the United Kingdom (or the Channel Islands or the Isle of Man). This is known as the

residency test . The way in which the test for central management and control is applied for the purposes of the City Code may be different from the way in which it is applied by the United Kingdom tax authorities, Her Majesty s

Revenue & Customs ( HMRC ). Under the City Code, the Panel looks to where the majority of the directors of the Company are resident, amongst other factors, for the purposes of determining where the Company has its place of

central management and control.

The Panel has confirmed to the Company that following the AIM Delisting, based on the current composition of the Board,

the City Code will continue to apply to the Company. However, the City Code could cease to apply to the Company in the future if any changes to the Board composition result in the majority of the Directors not being resident in the United Kingdom,

Channel Islands and Isle of Man.

Further details of the Panel, the City Code and the protections given by the City Code are set out in the Circular.

Shareholders are encouraged to read this information carefully as it outlines certain important protections which they will be giving up if they agree to the AIM Delisting and the Company subsequently ceases to be subject to the City Code.

The Board is seeking shareholder approval to an amendment to the Company s articles of association (the

Articles ) which would apply in the event that the City Code ceased to apply to the Company. This amendment would insert a new article 159 into the Articles which would apply in the event that the City Code were no longer to apply

to the Company. Article 159 includes certain takeover protections so that the Company is able to defend itself and its shareholders from hostile takeovers. An ordinary resolution will be put to shareholders at each annual general meeting, starting

with the annual general meeting in 2022, as to whether article 159 should continue to apply for the period until the next following annual general meeting. The full text of article 159 is set out in Appendix B to the Circular.

Information for holders of Ordinary Shares

resolutions are passed at the General Meeting, the Company s Ordinary Shares will continue to be traded on AIM until market close (4.30 p.m. London time) on 29 November 2021. Thereafter, holders of Ordinary Shares can still hold the

Ordinary Shares, but there will be no public market in the United Kingdom on which the Ordinary Shares can be traded, and the Ordinary Shares will not be tradeable on Nasdaq in this form.

To sell Ordinary Shares on a public market following the AIM Delisting, shareholders will need to deposit their Ordinary Shares for delivery of ADSs. Each ADS

represents three Ordinary Shares. This deposit can be made at any time, including before the AIM Delisting, subject in all cases to the provisions of, and the limitations set forth in, the New York law governed deposit agreement dated

4 September 2020 between the Company, the Bank of New York Mellon (the Depositary ) and all holders and beneficial owners of ADSs issued thereunder (the Deposit Agreement ).

The Board considers that shareholders should consider depositing their Ordinary Shares for delivery of ADSs prior to the AIM Delisting on 30 November

2021 for the following reasons:

Shareholders who do not elect to participate in the block transfer process can utilise the services of a broker who is able to

facilitate deposits of Ordinary Shares at the shareholder s convenience.

Shareholders whose Ordinary Shares are held in uncertificated form in

CREST and who wish to deposit their Ordinary Shares for delivery of ADSs, should contact their broker without delay to request that their Ordinary Shares are deposited.

Silence advises holders of Ordinary Shares to seek independent financial advice regarding the AIM Delisting and the deposit of their Ordinary Shares for

Information on the process to deposit Ordinary Shares for delivery of ADSs and the forms to be completed accompany the Circular. The

information and forms, and contacts at the Company s Receiving Agent, Link Group, in respect of completion of the block transfer participation request form for certificated holders, and the Depositary, The Bank of New York Mellon, are included

on Silence s website at www.silence-therapeutics.com.

If the Resolutions are not passed at the General Meeting, all documents provided to Link

Group and/or The Bank of New York Mellon in relation to the deposit of Ordinary Shares for delivery of ADSs shall be of no effect and all original share certificates will be returned to shareholders by Link Group.

Many investors purchase AIM-quoted shares because they are classed as unlisted/unquoted securities which may qualify individuals who are UK tax resident and UK domiciled for relief from inheritance taxation and certain other preferential

tax benefits. Silence cannot and does not provide any form of taxation advice to shareholders and therefore shareholders are strongly advised to seek their own taxation advice to confirm the consequences of continuing to hold unlisted Ordinary

Shares or depositing Ordinary Shares for delivery of ADSs.

The following summary does not constitute legal or tax advice and is not exhaustive. The

Company s understanding of the current position for UK individuals who are UK domiciled for relevant tax purposes is as follows but it should be noted that the position on certain points is not free from uncertainty and that the Company has not

taken steps to confirm the current position with HMRC. Therefore, the following should not be relied upon by shareholders without taking further advice (and the Company accepts no liability in respect of any such reliance on any information provided

herein on taxation matters):

Shareholders who elect to deposit their holdings of Ordinary

Shares for delivery of Nasdaq-listed ADSs prior to the AIM Delisting should not incur a stamp duty, or SDRT, charge. It is expected that shareholders who elect to deposit their holdings of Ordinary Shares for delivery of Nasdaq-listed ADSs following

the AIM Delisting may incur a stamp duty, or SDRT, charge at the rate of 1.5 per cent. of the market value of the Ordinary Shares being deposited.

It is strongly recommended that shareholders obtain appropriate professional advice in respect of these and other taxes.

Further information in relation to the AIM Delisting

Board believes that the proposed AIM Delisting is an appropriate next step for the Company and is in the best interests of shareholders as a whole. Further information about the process required to deposit Ordinary Shares for delivery of ADSs

tradeable on Nasdaq, together with a set of Frequently Asked Questions, accompany the Circular.

Details of the General Meeting and action to be taken

in respect of the General Meeting

A notice convening the General Meeting, which is to be held at 72 Hammersmith Road, London W14 8TH at 2.00 p.m.