Silence Therapeutics plc Announces That the Entire Shareholding Held by Introgen Inc Has Been Placed with Existing and New Shareholders

London, 17 January 2008 – Silence Therapeutics plc (LSE:SLN), a leading European RNAi therapeutics company, is pleased to announce that a number of existing institutional shareholders have increased their shareholdings in the Company, while several additional investors have become new shareholders. These shareholders have purchased their shares from Introgen Inc., which has disposed of its entire holding of 7,478,261 ordinary shares in Silence Therapeutics, representing approximately 6.2% of the issued share capital of the Company.

The shares were purchased at the prevailing market price of 56.75p per share and as necessary further regulatory announcements concerning this transaction will follow in due course.

Iain Ross, Chairman of Silence Therapeutics, commenting on today’s announcement said “I would like to thank Introgen for its support since it became a shareholder in 2005, particularly in backing our decision to focus on our RNAi chemistry and delivery technologies. I am very encouraged that some of our most important institutional investors have taken the opportunity to increase their investment in the Company and welcome our new shareholders. With the continued support of these high quality investors, I am confident that we will achieve our goal of becoming a global leader in the RNAi field, one of the most exciting areas of drug discovery and development.”

Enquiries:

For further information, please contact the following:

Silence Therapeutics plc Citigate Dewe Rogerson

+44(0)20 7307 1620 +44(0)20 7638 9571

Iain Ross, Chairman David Dible

Jeff Vick, Chief Executive Officer Emma Palmer

Melvyn Davies, Finance Director