Blocklisting - Interim Review

MICROGEN PLC
22 JANUARY 2009

                             BLOCK LISTING RETURN                              


Name of applicant:       MICROGEN PLC

Name of scheme:          MICROGEN PLC 1997 AND 1999 EXECUTIVE SHARE OPTION SCHEME

                         MICROGEN PLC 1996 SAVINGS RELATED SHARE OPTION SCHEME

Period of return: From:  1 JULY 2008     To:  31 DECEMBER 2008

Balance under scheme from previous return:

MICROGEN PLC 1997 AND 1999 EXECUTIVE SHARE OPTION SCHEME - 345,500 ORDINARY SHARES OF 5P EACH

MICROGEN PLC 1996 SAVINGS RELATED SHARE OPTION SCHEME - 82,291 ORDINARY SHARES OF 5P EACH

The amount by which the block scheme has
been increased, if the scheme has been
increased since the date of the last return:   N/A

Number of securities issued/allotted under
scheme during period:

MICROGEN PLC 1997 AND 1999 EXECUTIVE SHARE OPTION SCHEME - 10,000 ORDINARY SHARES OF 5P EACH

MICROGEN PLC 1996 SAVINGS RELATED SHARE OPTION SCHEME - 0 ORDINARY SHARES OF 5P EACH

Balance under scheme not yet issued/allotted
at end of period

MICROGEN PLC 1997 AND 1999 EXECUTIVE SHARE OPTION SCHEME - 335,500 ORDINARY SHARES OF 5P EACH

MICROGEN PLC 1996 SAVINGS RELATED SHARE OPTION SCHEME - 82,291 ORDINARY SHARES OF 5P EACH

Number and class of securities originally
listed and the date of admission

MICROGEN PLC 1997 AND 1999 EXECUTIVE SHARE OPTION SCHEME - 800,000 ORDINARY SHARES OF 5P EACH

MICROGEN PLC 1996 SAVINGS RELATED SHARE OPTION SCHEME - 200,000 ORDINARY SHARES OF 5P EACH

15 APRIL 2005

Total number of securities in issue at the end
of the period

86,830,192 ORDINARY SHARES OF 5P EACH

Name of contact:              ANJUM SIDDIQI, COMPANY SECRETARY
Address of contact:           FLEET HOUSE, 3 FLEETWOOD PARK, BARLEY WAY, HANTS, GU51 2QJ
Telephone number of contact:  01252 772 326

www.microgen.com