SLN.L Regulatory News (SLN)

Appointment of chief executive and director of corporate development

29th May 2013

Silence Therapeutics plc (AIM: SLN) announces today the appointment of Ali Mortazavi as chief executive and of Annie Cheng as director of corporate development.

Ali Mortazavi joined Silence in August 2012 as director of corporate strategy and since that time has increasingly taken on the mantle of the CEO role. This included overseeing two fundraisings last year to raise £11m for the company and spearheading the £19m placing completed in April 2013. Ali has over 17 years of experience in financial services. He started his career as a Technology Analyst at Duncan Lawrie then Credit Lyonnais Securities. In 2001, he co-founded Evolution Securities and ran the principal trading and market making arm, leaving in 2008. He has extensive experience in small companies and has had significant stakes in UK listed technology / biotech ventures.

Annie Cheng (Annie Jia Huey Cheng), age 37, joins the company after working as a strategy consultant for the Company since October 2012. She has 14 years of experience in the healthcare industry, in equity research and consulting with JP Morgan and boutique investment banks in New York and London.

She has been a director of Visible Value LLP, a biotech consultancy, since December 2011 and of Valor Visible Ltd, its associated business, since October 2012.

There are no other matters to disclose regarding her appointment under Rule 17 or Schedule 2 paragraph (g) of the AIM Rules for Companies.

Chairman Jerry Randall said: 'Ali brings a wealth of experience in the capital markets as well as small cap companies, and has been instrumental in the development of Silence since he joined. Annie's combination of investor and commercial experience is very valuable.'

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