TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARES

24 Aug 2012 14:41

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 PLCattached:ii 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 Richard Griffithsnotification 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 22 August 2012reached: v 6. Date on which issuer notified: 24 August 2012 7. Threshold(s) that is/are crossed or 5%reached: vi, vii 8. Notified details: A: Voting rights attached to shares viii, ix Class/type of Situation previous Resulting situation after the triggering transaction shares to the triggering transaction if possible Number Number Number Number of voting % of voting rightsusing of of of shares rights x the ISIN CODE Shares Voting Rights Direct Direct xi Indirect Direct Indirect xii GB0008433350 60,850,538 4.15% 84,636,511 84,636,511 5.77% B: Qualifying Financial Instruments Resulting situation after the triggering transaction Type of financial Expiration Exercise/ Number of voting % of voting instrument date xiii Conversion Period xiv rights that may be rights acquired if the instrument is exercised/ converted. 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 Total (A+B+C) Number of voting rights Percentage of voting rights 84,636,511 5.77%

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: Chris Hill 15. Contact telephone number: 01481 738724 Note: Annex should only be submitted to the FSA not the issuer Annex: Notification of major interests in sharesxxii A: Identity of the persons or legal entity subject to the notification obligation Full name (including legal form of legal entities) Contact address (registered office for legal entities) Phone number & email Other useful information (at least legal representative for legal persons)

B: Identity of the notifier, if applicable Full name Contact address Phone number & email Other useful information (e.g. functional relationship with the person or legal entity subject to the notification obligation) C: Additional information

For notes on how to complete form TR-1 please see the FSA website.