Cancellation of warrants

Silence Therapeutics plc ("Silence" or the "Company")

CANCELLATION OF WARRANTS

03 July 2013

The Company has agreed to buy back and cancel the 66,600 warrants, exercisable at 75p, issued to Darwin Strategic Ltd for a payment of £70,000. This was the fair value of the warrants on 4 June 2013, the date Silence published its annual report. Darwin is 37% owned by Ali Mortazavi, the chief executive of Silence.

For further information please contact:

Silence Therapeutics

Ali Mortazavi, chief executive/Timothy Freeborn, finance director +44 (0)333 988 0140

a.mortazavi@silence-therapeutics.com

t.freeborn@silence-therapeutics.com

N+1 Singer

Shaun Dobson/Jenny Wyllie

+44 20 7496 3000

shaun.dobson@n1singer.com

jenny.wyllie@n1singer.com