Offer Update

Microgen plc

10 September 2004

NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION IN WHOLE OR IN PART IN OR INTO THE
                   UNITED STATES, CANADA, AUSTRALIA OR JAPAN                   

                             RECOMMENDED OFFER BY                              

                              UBS INVESTMENT BANK                              

                                 ON BEHALF OF                                  

                                 MICROGEN plc                                  

                                      FOR                                      

                                AFA SYSTEMS plc                                

Offer declared unconditional in all respects save for Admission of the New
Microgen Shares.

The Board of Microgen plc announces that all of the conditions of the Offer as
set out in the Offer Document dated 18 August 2004 have now been satisfied or
waived, subject only to the Admission of the New Microgen Shares. Accordingly,
the Offer is declared unconditional in all respects, save for Admission of the
New Microgen Shares. It is expected that Admission will become effective and
that dealings in the New Microgen Shares will commence on the London Stock
Exchange at 8.00 am on Monday 13 September 2004.


The Offer will remain open for acceptance until further notice, subject to the
terms and conditions set out in the Offer Document. However, as announced on 9
September 2004, the Mix and Match Facility closed at 3.00 pm on 9 September
2004.

Consideration payable under the Offer will be dispatched (in the manner set out
in the Offer Document) by 26 September 2004 to those AFA Shareholders in
respect of whom valid acceptances have already been received. Consideration in
respect of valid acceptances of the Offer received from today onwards will be
dispatched to accepting AFA Shareholders within 14 days of such receipt.

Terms defined in the Offer Document and the Listing Particulars dated 18 August
2004 shall have the same meaning in this announcement.

This announcement does not constitute an offer or an invitation to purchase or
subscribe for any securities. The Offer is made solely by the Offer Document
and the Form of Acceptance accompanying the Offer Document, which contain the
full terms and conditions of the Offer, including details of how the Offer may
be accepted.

The Offer is not being made, directly or indirectly, in or into, or by the use
of mails or any means of instrumentality (including, without limitation,
telephonically or electronically) of interstate or foreign commerce, or any
facility of a national securities exchange, of the United States, Canada,
Australia or Japan and the Offer cannot be accepted by any such use, means,
instrumentality, facility or otherwise from within the United States, Canada,
Australia or Japan. Accordingly, copies of this announcement, the Offer
Document, the Form of Acceptance and any accompanying documents are not being,
and must not be mailed or otherwise distributed or sent in, into or from the
United States, Canada, Australia or Japan and persons receiving such documents
(including nominees, trustees and custodians) must not distribute or send them
in, into or from the United States, Canada, Australia or Japan. Doing so may
render invalid any purported acceptance of the Offer.

The availability of the Offer to persons who are not resident in the United
Kingdom may be affected by the laws of the relevant jurisdictions. Persons who
are not resident in the United Kingdom should inform themselves about and
observe any applicable requirements. Further details in relation to Overseas
Shareholders are contained in the Offer Document.

The New Microgen Shares to be issued in connection with the Offer have not
been, nor will they be, registered under the Securities Act or under the
securities laws of any jurisdiction of the United States, nor has a prospectus
in relation to the New Microgen Shares been lodged with, or registered by, the
Securities Commission of any province or territory of Canada or the Australian
Securities and Investments Commission or the Ministry of Japan. Accordingly,
the New Microgen Shares may not be offered, sold, resold or delivered, directly
or indirectly, in or into the United States, Canada, Australia or Japan or any
other jurisdiction outside the United Kingdom in which the offer of New
Microgen Shares would constitute a violation of relevant laws or require
registration thereof.

UBS is acting exclusively for Microgen in connection with the Offer and no-one
else and will not be responsible to anyone other than Microgen for providing
the protections afforded to clients of UBS or for providing advice in relation
to the Offer or in relation to the contents of this announcement or any
transaction or arrangement referred to herein.

Microgen

Mike Phillips, Group Finance Director

Phone: [phone]

UBS Investment Bank

Nick Adams

Phone: [phone]

Financial Dynamics

Giles Sanderson

Phone: [phone]