Posting of Shareholder Circular

Monday 2 August 2010

Microgen plc: Posting of Shareholder Circular

Microgen plc's ("Microgen" or the "Company") interim results released on 22 July 2010 provided details of a proposed tender offer.

Microgen today announces that it has posted to its shareholders a copy of the circular (the "Shareholder Circular") setting out full details of the proposed tender offer. The Shareholder Circular also contains a notice of a General Meeting of the Microgen shareholders to be held at Fleet House, 3 Fleetwood Park, Barley Way, Fleet, Hampshire, GU51 2QJ on 19 August 2010 at 9:00a.m.

Copies of the Shareholder Circular will be available for inspection during normal business hours at the registered office of Microgen and at the London office of the Company's solicitors, Berwin Leighton Paisner LLP. A copy of the Circular will also be available at the venue of the General Meeting for at least 15 minutes before the General Meeting commences and for the duration of the meeting.

The Shareholder Circular has also been submitted to the UK Listing Authority's Document Viewing Facility, which is situated at:

The Financial Services Authority

25 The North Colonnade

Canary Wharf

London

E14 5HS

The Shareholder Circular is also available on Microgen's website at: http://www.microgen.com

Contact:

Martyn Ratcliffe, Chairman 01252 772300

David Sherriff, Chief Operating Officer

Philip Wood, Group Finance Director

James Melville-Ross, Financial Dynamics 020 7831 3113

Haya Herbert-Burns, Financial Dynamics

Michael Lacey-Solymar, Investec 020 7597 4000

Rowena Murray, Investec

Investec Investment Banking, which is regulated for designated investment business in the UK by the Financial Services Authority, is acting for Microgen plc and no one else in connection with the Tender Offer and will not be responsible to anyone other than Microgen plc for providing the protections afforded to customers of Investec Investment Banking Ltd or for providing advice in relation thereto or for advising any such person on the contents of this document or any transaction or agreement referred to herein.

Overseas Shareholders should inform themselves about and observe any applicable legal or regulatory requirements. If they are in any doubt about their position, they should consult their professional advisor in the relevant territory.