TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARES

17th May 2011 17:38

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 Therapeutics Plc of existing shares to which voting rights are

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 ROBERT KEITH

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 17th May 2011

reached: v

6. Date on which issuer notified: 17th May 2011 7. Threshold(s) that is/are crossed or 8%

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 rights x using of of of shares rights the ISIN CODE Shares Voting Rights Direct Direct xi Indirect Direct Indirect xii GB0008433350 12,217,138 1,000,000 62,217,138 51,000,000 8.84%

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. N/A C: Financial Instruments with similar economic effect to Qualifying Financial Instruments xv, xvi

Resulting situation after the triggering transaction

Type of financial Exercise Expiration Exercise/ Number of voting rights % of voting rights instrument price date xvii Conversion instrument refers to xix, xx period xviii Nominal Delta N/A Total (A+B+C) Number of voting rights Percentage of voting rights 51,000,000 8.84%

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: Richard Beech 15. Contact telephone number: 0161 828 0233

vendor

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Related Shares:

SLN.L