Fundraising update

THIS ANNOUNCEMENT IS NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, DIRECTLY OR INDIRECTLY, IN WHOLE OR IN PART, IN, INTO OR FROM THE UNITED STATES, CANADA, AUSTRALIA, THE REPUBLIC OF SOUTH AFRICA, THE REPUBLIC OF IRELAND OR JAPAN OR ANY OTHER JURISDICTION WHERE TO DO SO WOULD CONSTITUTE A BREACH OF THE RELEVANT SECURITIES LAWS OF SUCH JURISDICTION.

This announcement does not constitute a prospectus or offering memorandum or an offer in respect of any securities and is not intended to provide the basis for any decision in respect of Silence Therapeutics PLC or other evaluation of any securities of Silence Therapeutics PLC or any other entity and should not be considered as a recommendation that any investor should subscribe for or purchase any such securities.

8 April 2015

SILENCE THERAPEUTICS PLC("Silence Therapeutics" or the "Company")Fundraising Update

The Company announces that, further to the Fundraising announced on 2 April 2015, Canaccord Genuity Limited and Peel Hunt LLP (the "Joint Bookrunners") have exercised the Broker Option and have conditionally placed 5,294,998 new Ordinary Shares (the "Broker Option Shares") with new and existing institutional investors, meaning that the Broker Option Shares have been subscribed for in full.The Broker Option Shares are being placed at a price of 240 pence per Broker Option Share (being the same as the Issue Price), pursuant to the same terms and conditions as the Placing Shares. All of the proceeds of £12.7 million (before expenses) arising from the placing of the Broker Option Shares will be received by the Company. Subject to the Fundraising completing, the Company therefore expects to raise total net proceeds of approximately £38.9 million.

The Placing and the Broker Option remain subject to, inter alia, the approval by Shareholders of the Resolutions at the General Meeting, which has been convened at 10.00 a.m. on 1 May 2015 at the Company's offices, 1 Lyric Square, London W6 0NB. Subject to the approval by Shareholders of the Resolutions, application will be made to the London Stock Exchange for the Placing Shares and the Broker Option Shares to be admitted to trading on AIM with Admission expected to become effective at 8.00am on 8 May 2015.

The Circular relating to the Fundraising has today been posted to Shareholders.

For further information contact:

EXPECTED TIMETABLE OF PRINCIPAL EVENTS

KEY STATISTICS

Certain statements in this Announcement are forward-looking statements which are based on the Company's expectations, intentions and projections regarding its future performance, anticipated events or trends and other matters that are not historical facts. These forward-looking statements, which may use words such as "aim", "anticipates", "believe", "intend", "estimate", "expect" and words of similar meaning, include all matters that are not historical facts. These forward-looking statements involve risks and uncertainties that could cause the actual results of operations, financial condition, liquidity, dividend policy and the development of the industry in which the Company's business operates to differ materially from the impression created by the forward-looking statements. These statements are not guarantees of future performance and are subject to known and unknown risks, uncertainties and other factors that could cause actual results to differ materially from those expressed or implied by such forward-looking statements. Given these risks and uncertainties, prospective investors are cautioned not to place undue reliance on forward-looking statements. Forward-looking statements speak only as of the date of such statements and, except as required by the FCA, the London Stock Exchange or applicable law, the Company undertakes no obligation to update or revise publicly any forward-looking statements, whether as a result of new information, future events or otherwise.

The Placing Shares and Broker Option Shares will not be admitted to trading on any stock exchange other than the AIM market of the London Stock Exchange.

IMPORTANT NOTICE

This announcement has been issued by, and is the sole responsibility of, Silence Therapeutics. No person has been authorised to give any information or to make any representations other than those contained in this announcement and, if given or made, such information or representations must not be relied on as having been authorised by the Company, Canaccord Genuity or Peel Hunt.

This announcement is for information purposes only and does not constitute or form part of any offer to issue or sell, or the solicitation of an offer to acquire, purchase or subscribe for, any securities of the Company in any jurisdiction and should not be relied upon in connection with any decision to subscribe for or acquire any such securities. In particular, this announcement does not constitute an offer to sell, or a solicitation of an offer to buy, securities in the United States. Members of the public will not be eligible to take part in any placement of the securities of Silence Therapeutics described herein.

Any securities of the Company described in this announcement have not been, and will not be, registered under the U.S. Securities Act of 1933, as amended (the "US Securities Act"), or under the securities laws of any state or other jurisdiction of the United States and may not be offered, sold, resold, transferred or delivered, directly or indirectly, in, into or within the United States except pursuant to an applicable exemption from, or in a transaction not subject to, the registration requirements of the US Securities Act. Furthermore, the securities of the Company described in this announcement have not been and will not be registered under the applicable laws of any of Canada, Australia, New Zealand, Japan, the Republic of Ireland or South Africa and, consequently, may not be offered or sold to any national, resident or citizen thereof.

The distribution of this announcement, in whole or in part, directly or directly, in or into jurisdictions other than the United Kingdom may be restricted by law and therefore any person who is subject to the laws of any jurisdiction other than the United Kingdom should inform themselves about, and observe such restrictions. Any failure to comply with the applicable restrictions may constitute a violation of the securities laws of any such jurisdiction. Subject to certain exceptions, this document is not for release, publication or distribution, directly or indirectly, in whole or in part, in or into the United States, Canada, Australia, New Zealand, Japan, the Republic of Ireland, South Africa or any jurisdiction where to do so might constitute a violation of local securities laws or regulations.

No prospectus or offering document has been or will be prepared in connection with the Placing and/or the Broker Option. Any investment decision to buy securities in the Placing and/or the Broker Option must be made solely on the basis of publicly available information. Such information is not the responsibility of, and has not been independently verified by, Canaccord Genuity or Peel Hunt or any of their respective affiliates.

This announcement and any offer of securities to which it relates are only addressed to and directed at persons who: (A) if in the United Kingdom, are persons who are (i) "qualified investors" as defined in section 86(7) of the Financial Services and Markets Act 2000 and who are investment professionals falling within Article 19(1) or Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the "Order") or (ii) high net worth companies, unincorporated associations or partnerships or trustees of high value trusts as described in Article 49(2)(a) to (d) of the Order or (iii) other persons to whom it may otherwise lawfully be communicated; (B) if in a Member State of the European Economic Area, are persons who are "qualified investors" within the meaning of Article 2(1)(e) of the Prospectus Directive (which means Directive 2003/71/EC and includes any relevant implementing directive measure in any Member State), and/or (C) in the United States, "accredited investors" as defined in Rule 501 of the U.S. Securities Act, (all such persons referred to in (A),(B) and (C) together being "Relevant Persons"). The information regarding the Placing and the Broker Option set out in this announcement must not be acted on or relied on by persons who are not Relevant Persons. Any investment or investment activity to which this announcement relates is available only to Relevant Persons and will be engaged in only with Relevant Persons.

Canaccord Genuity Limited, which is authorised and regulated in the United Kingdom by the Financial Conduct Authority, is acting exclusively for the Company as Nominated Adviser and Joint bookrunner to Silence Therapeutics for the purposes of the AIM Rules for Companies and the AIM Rules for Nominated Advisers in connection with any placement of the securities of Silence Therapeutics described herein and admission of such securities and is not acting for, and will not be responsible to, any person other than Silence Therapeutics for providing the protections afforded to customers of Canaccord Genuity Limited or for advising any other person on any transaction or arrangement referred to in this announcement.

Peel Hunt LLP, which is authorised and regulated in the United Kingdom by the Financial Conduct Authority, is acting exclusively for the Company as Joint bookrunner in connection with any placement of the securities of Silence Therapeutics described herein and admission of such securities and is not acting for, and will not be responsible to, any person other than Silence Therapeutics for providing the protections afforded to customers of Peel Hunt LLP or for advising any other person on any transaction or arrangement referred to in this announcement.