Subscription and Conversion

28 November 2012

Silence Therapeutics plc

("Silence" or the "Company")

Subscription of New Ordinary Shares and conversion of £1m loan note

Subscription

The Board of Silence is pleased to announce a fundraising of £5 million (before expenses) through the issue of 200,000,000 new ordinary shares by way of a subscription at 2.5 pence per ordinary share (the "Subscription") to Henderson Global Investors (160,000,000 shares) and Ora Capital (Guernsey) Limited (40,000,000 shares). The placing price represents a discount of approximately 19 per cent. to the middle market price of 3.1 pence per share, being the middle market closing price of the Company's ordinary shares on 27 November 2012. The Subscription does not require shareholder approval.

Application has been made to have the shares admitted to trading on AIM. Admission and commencement of the new ordinary shares to trading is expected to take place at 8 a.m. on 30 November 2012.

The Directors intend that the amount of £5 million (before expenses) being raised from the Subscription will be used to expand the Company's research activities in short interfering RNA and micro RNA therapies. The proceeds of the Subscription will enhance the Company's financial position and provide it with sufficient cash resources to fund the business well into 2014, even without generating any revenue.

Conversion of £1m loan note

Robert Keith has given written notice to convert his £1m loan note into 200,000,000 new ordinary shares at 0.5 pence per share (the "Conversion"). The loan note was issued in July 2012 as part of the Company's refinancing. The Conversion releases the Company and its subsidiary, Silence Therapeutics AG, from charges over intellectual property. Silence will instruct Capita, the Company's registrar, to issue the new ordinary shares as soon as possible and application has been made to have the shares admitted to trading on AIM. Admission and commencement of the new ordinary shares to trading is also expected to take place at 8 a.m. on 30 November 2012.

The shares issued in relation to the Subscription and the Conversion will rank pari passu in all respects with the Company's existing fully paid ordinary shares. Following the Subscription and the Conversion, there will be 1,870,202,737 ordinary shares of 0.1p each in issue.

Ali Mortazavi, Director of Corporate Strategy, said:

"We are delighted to welcome Henderson as a significant shareholder in Silence. Along with further support from our existing shareholders, the Company is now ideally placed to take advantage of the new wave in RNAi therapeutics."

For further information please contact:

THIS ANNOUNCEMENT AND THE INFORMATION CONTAINED HEREIN IS RESTRICTED AND IS NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, DIRECTLY OR INDIRECTLY, IN WHOLE OR IN PART, IN OR INTO THE UNITED STATES, AUSTRALIA, CANADA, JAPAN, NEW ZEALAND OR THE REPUBLIC OF SOUTH AFRICA OR ANY OTHER JURISDICTION IN WHICH THE SAME WOULD BE UNLAWFUL.

THIS ANNOUNCEMENT IS FOR INFORMATION PURPOSES ONLY AND DOES NOT CONSTITUTE OR FORM PART OF ANY OFFER OR INVITATION TO SELL OR ISSUE, OR ANY SOLICITATION OF ANY OFFER TO PURCHASE OR SUBSCRIBE FOR, ANY NEW ORDINARY SHARES, NOR SHALL IT (OR ANY PART OF IT), OR THE FACT OF ITS DISTRIBUTION, FORM THE BASIS OF, OR BE RELIED ON IN CONNECTION WITH OR ACT AS ANY INDUCEMENT TO ENTER INTO, ANY CONTRACT OR COMMITMENT WHATSOEVER WITH RESPECT TO THE PROPOSED SHARE CAPITAL REORGANISATION, SUBSCRIPTION, ISSUE OF CONVERTIBLE LOAN NOTE, OPEN OFFER OR ESTABLISHMENT OF AN EQUITY FINANCE FACILITY OR OTHERWISE. THIS ANNOUNCEMENT IS NOT A CIRCULAR AND INVESTORS SHOULD NOT SUBSCRIBE FOR OR PURCHASE ANY NEW ORDINARY SHARES REFERRED TO IN THIS ANNOUNCEMENT EXCEPT SOLELY ON THE BASIS OF INFORMATION IN THE CIRCULAR EXPECTED TO BE PUBLISHED TODAY. COPIES OF THE CIRCULAR WILL, FOLLOWING PUBLICATION, BE AVAILABLE FROM SILENCE THERAPEUTICS' OFFICES AT THE ROYAL INSTITUTION OF GREAT BRITAIN, 21 ALBEMARLE STREET, LONDON, W1S 4BS.

THE SECURITIES MAY NOT BE OFFERED OR SOLD IN THE UNITED STATES, UNLESS REGISTERED UNDER THE U.S. SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR PURSUANT TO AN EXEMPTION FROM SUCH REGISTRATION. NO PUBLIC OFFERING OF THE SECURITIES DISCUSSED HEREIN IS BEING MADE IN THE UNITED STATES AND THE INFORMATION CONTAINED HEREIN DOES NOT CONSTITUTE AN OFFERING OF SECURITIES FOR SALE IN THE UNITED STATES AND THE COMPANY DOES NOT CURRENTLY INTEND TO REGISTER ANY SECURITIES UNDER THE SECURITIES ACT. THIS ANNOUNCEMENT IS NOT FOR DISTRIBUTION DIRECTLY OR INDIRECTLY IN OR INTO THE UNITED STATES.

Notes for editors

About Silence Therapeutics plc (www.silence-therapeutics.com)

Silence Therapeutics plc (AIM: SLN) is a leading biotechnology company dedicated to the discovery, development and delivery of targeted, systemic RNA interference (RNAi) therapeutics for the treatment of serious diseases. Silence offers one of the most comprehensive short interfering RNA (siRNA) therapeutic platforms available today based on a strong intellectual property portfolio and large clinical safety database. Silence's clinical siRNA product pipeline is one of the broadest in the industry. The Company possesses multiple proprietary siRNA delivery technology platforms including AtuPLEX™, DACC and DBTC. AtuPLEX enables the broad functional delivery of siRNA molecules to targeted diseased tissues and cells, while increasing their bioavailability and intracellular uptake. The DACC delivery system allows functional delivery of siRNA molecules selectively to the lung endothelium with a long duration of target mRNA and protein knock-down. The DBTC delivery system enables functional delivery of siRNA molecules selectively to liver cells including hepatocytes. Additionally, the Company has a platform of novel siRNA molecules based around its AtuRNAi chemical modification technology, which provides a number of advantages over conventional siRNA molecules. Silence's unique RNAi assets also include structural features for RNAi molecules and specific design rules for increased potency and reduced off-target effects of siRNA sequences.

The Company's lead internal drug candidate is Atu027, a liposomal formulation in clinical development for systemic cancer indications and one of the most clinically advanced RNAi therapeutic candidates in the area of oncology. Atu027 incorporates two of the Company's technologies, AtuRNAi and AtuPLEX™.

The Company's RNAi therapeutic platform has received key validation through multiple partnerships with pharmaceutical companies including AstraZeneca, Dainippon Sumitomo, Pfizer/Quark, and Novartis/Quark. Silence is actively pursuing the establishment of additional partnerships. Silence Therapeutics has laboratories in Berlin and is headquartered in London.