Offer Document Posted

Microgen PLC
01 June 2007


For immediate release

1 June 2007

NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, IN WHOLE OR IN PART, IN OR INTO
THE UNITED STATES OF AMERICA, CANADA, AUSTRALIA OR JAPAN OR ANY JURISDICTION
WHERE TO DO SO WOULD CONSTITUTE A VIOLATION OF THE RELEVANT LAWS OF SUCH
JURISDICTION

 Recommended Cash Offer for the entire issued and to be issued share capital of
             Trace Group plc ('Trace') by Microgen plc ('Microgen')

                             Offer Document Posted

Further to the announcement on 25 May 2007 by Microgen regarding the recommended
cash offer at a price of 155 pence per Trace Share, the Board of Microgen 
announces that the Offer Document is today published and is being posted to 
Trace Shareholders.

To accept the Offer in respect of Trace Shares held in certificated form (that
is, not through CREST), Trace Shareholders should complete, sign and return the
Form of Acceptance (which has been posted to Trace Shareholders along with the 
Offer Document) in accordance with the instructions thereon and the instructions
in the Offer Document as soon as possible and, in any event, so as to be 
received by Capita Registrars by no later than 1.00 p.m. London time on 25 June 
2007. To accept the Offer in respect of Trace Shares held in uncertificated form
(that is, through CREST), Trace Shareholders should submit a TTE instruction in 
accordance with the instructions in the Offer Document for settlement as soon as
possible and, in any event, by no later than 1.00 p.m. London time on 25 June 
2007.

The Offer Document will be available for inspection on Microgen's website -
www.microgen.co.uk and copies of the Offer Document and the Form of Acceptance
(for use by holders of Trace Shares in certificated form only) will be available
for inspection during normal business hours on any weekday (Saturdays, Sundays
and public holidays excepted) at the registered office of Clyde & Co LLP at 51
Eastcheap, London EC3M 1JP until the end of the Offer Period.

Capitalised terms used, but not defined in this announcement have the same
meaning as given to them in the Offer Document.

Enquiries:
Microgen plc                             Tel: [phone]
Martyn Ratcliffe
Philip Wood

Arbuthnot Securities Limited             Tel: [phone]
(Financial adviser and broker to Microgen in relation to the Offer)
Ian Williams
Richard Tulloch

Financial Dynamics Tel: [phone]
(Public relations adviser to Microgen)
Giles Sanderson

Arbuthnot Securities, which is authorised and regulated in the United Kingdom by
the Financial Services Authority, is acting exclusively for Microgen and no one
else in connection with the Offer and will not be responsible to anyone other
than Microgen for providing the protections afforded to clients of Arbuthnot
Securities nor for providing advice in relation to the Offer, or the contents of
this Announcement or any matter referred to herein.

This announcement is not intended to and does not constitute, or form any part
of, an offer or an invitation to purchase or sell any securities or the
solicitation of any vote or approval in any jurisdiction pursuant to the Offer
or otherwise. The Offer will be made solely through the Offer Document, and, in
relation to certificated Trace Shares, the Form of Acceptance. The Offer
Document and the Form of Acceptance will together contain the full terms and
conditions of the Offer, including details of how to accept the Offer. Any
acceptance or other response to the Offer should be made only on the basis of
the information contained in the Offer Document and the Form of Acceptance. The
Offer will be subject to English Law. The laws of relevant jurisdictions may
affect the availability of the Offer to overseas persons. Overseas persons, or
persons who are subject to the laws of any jurisdiction other than the United
Kingdom, should inform themselves about and observe any applicable legal and
regulatory requirements. The Offer Document will be available for public
inspection in the United Kingdom.

Unless otherwise determined by Microgen, the Offer will not be made, directly or
indirectly, in or into the United States or by use of the mails of, or by any
means or instrumentality (including, without limitation, facsimile, internet,
email or other electronic transmission, telex or telephone) of inter-state or
foreign commerce of, or any facility of a national, state or other securities
exchange of, the United States, nor will it be made directly or indirectly in or
into Canada, Australia, Japan or any Restricted Jurisdiction, and the Offer will
not be capable of acceptance by any such use, means, instrumentality or facility
or from within the United States, Canada, Australia, Japan or any Restricted
Jurisdiction. Accordingly, copies of this announcement are not being, will not
be and must not be, directly or indirectly, mailed or otherwise forwarded,
transmitted, distributed or sent in, into or from the United States, Canada,
Australia, Japan or any Restricted Jurisdiction, and persons receiving this
announcement (including, without limitation, custodians, nominees and trustees)
must not mail, forward, distribute or send it in, into or from the United
States, Canada, Australia, Japan or any Restricted Jurisdiction. Doing so may
render invalid any purported acceptance of the Offer. Any persons (including
custodians, nominees and trustees) who are overseas persons or who would, or
otherwise intend to, mail or otherwise forward, transmit, distribute or send
this Announcement, the Offer Document, the Form of Acceptance or any related
document outside the United Kingdom or to any overseas person should seek
appropriate advice before doing so.



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