TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARES

12th May 2011 17:42

For filings with the FSA include the annex For filings with issuer exclude the annex TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARESi 1. Identity of the issuer or the underlying issuer Silence Therapeuticsof existing shares to which voting rights are Plc attached:ii (GB0008433350) 2 Reason for the notification (please tick the appropriate box or boxes): An acquisition or disposal of voting rights x An acquisition or disposal of qualifying financial instruments which may result in the acquisition of shares already issued to which voting rights are attached An acquisition or disposal of instruments with similar economic effect to qualifying financial instruments An event changing the breakdown of voting rights Other (please specify): 3. Full name of person(s) subject to the Commerzbank AG notification obligation:iii 4. Full name of shareholder(s) (if different from 3.):iv 5. Date of the transaction and date on which the threshold is crossed or 11th May 2011 reached: v 6. Date on which issuer notified: 12th May 2011 7. Threshold(s) that is/are crossed or 6% reached: vi, vii 8. Notified details: A: Voting rights attached to shares viii, ix

Class/type Situation previous Resulting situation after the triggering of

to the triggering transaction shares transaction Number Number Number Number of voting % of voting if possible of of of shares rights rights x using Shares Voting the ISIN Rights Direct Direct Indirect xii Direct IndirectCODE xi GB0008433350 16,503,638 5.9% 16,967,638 6.06% B: Qualifying Financial Instruments Resulting situation after the triggering transaction Type of Expiration Exercise/ Number of voting % of voting financial date xiii Conversion Period xiv rights that may be rights instrument acquired if the instrument is exercised/ converted. N/A C: Financial Instruments with similar economic effect to Qualifying Financial Instruments xv, xvi Resulting situation after the triggering transaction Type of Exercise Expiration Exercise/ Number of voting rights % of voting financial price date xvii Conversion instrument refers to rights xix, xx instrument period xviii Nominal Delta N/A Total (A+B+C) Number of voting rights Percentage of voting rights 16,967,638 6.06%

9. Chain of controlled undertakings through which the voting rights and/or the financial instruments are effectively held, if applicable: xxi

Proxy Voting: 10. Name of the proxy holder: 11. Number of voting rights proxy holder will cease to hold: 12. Date on which proxy holder will cease to hold voting rights: 13. Additional information: 14. Contact name: Reena Kolotia 15. Contact telephone number: 020 7475 1995

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Related Shares:

SLN.L