Offer Update

Microgen plc

13 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.

Following Admission becoming effective and dealings in the New Microgen Shares
commencing on the London Stock Exchange earlier today, the Board of Microgen
plc ('Microgen') announces that the Offer is declared unconditional in all
respects.

As at 3.00p.m. (London time) on 10 September 2004, Microgen had received valid
acceptances of the Offer in respect of a total of 40,906,062 AFA Shares,
representing approximately 86.69 per cent. of the existing issued ordinary
share capital of AFA Systems plc ('AFA').

As at 3.00p.m. (London time) on 10 September 2004, valid acceptances of the
Offer in relation to 6,119,097 AFA Shares, representing approximately 12.97 per
cent. of the existing issued ordinary share capital of AFA, had been received
electing for the basic terms of the Offer, valid acceptances of the Offer in
relation to 20,462,416 AFA Shares, representing approximately 43.37 per cent.
of the existing issued ordinary share capital of AFA, had been received
electing for additional cash under the Mix and Match Facility and valid
acceptances of the Offer in relation to 14,324,549 AFA Shares, representing
approximately 30.36 per cent. of the existing issued ordinary share capital of
AFA, had been received electing for additional shares under the Mix and Match
Facility. Prior to the posting of the Offer Document on 18 August 2004,
Microgen had received irrevocable undertakings and non-binding letters of
intent from AFA Directors and certain other AFA Shareholders to accept, or
procure the acceptance of, the Offer in respect of, in aggregate, 22,731,692
AFA Shares, representing approximately 48.18 per cent. of the existing issued
ordinary share capital of AFA. Valid acceptances of the Offer set out above
include acceptances in respect of all of the AFA Shares received pursuant to
such irrevocable undertakings and non-binding letters of intent

The Offer will remain open for acceptance until further notice, although the
Mix and Match Facility is now closed.

AFA Shareholders who wish to accept the Offer, and who have not yet done so,
should complete, sign and return their Forms of Acceptance, in accordance with
the instructions set out in the Offer Document and in the Form of Acceptance,
so as to be received as soon as possible. If AFA Shares are held in CREST,
acceptance should be made electronically so that the TTE Instruction settles as
soon as possible.

Save as disclosed in this announcement, the Offer Document and the listing
particulars in respect of New Microgen Shares which accompanies the Offer
Document, ('Listing Particulars') prior to the commencement of the Offer Period
on 13 August 2004, neither Microgen, nor any persons acting or deemed to be
acting in concert with Microgen, held any AFA Shares (or any rights over AFA
Shares), and neither Microgen nor any persons acting or deemed to be acting in
concert with Microgen, have since acquired or agreed to acquire any AFA Shares
(or any rights over AFA Shares).

The Offer remains subject to the terms and conditions set out in the Offer
Document dated 18 August 2004.

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]

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