Blocklisting - Interim Review

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: 31 MARCH 2006 To: 30 OCTOBER 2006

Balance under scheme from previous return:

MICROGEN PLC 1997 AND 1999 EXECUTIVE SHARE OPTION SCHEME - 704,000 ORDINARY SHARES OF 5P EACH

MICROGEN PLC 1996 SAVINGS RELATED SHARE OPTION SCHEME - 87,853 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 - 105,500 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 - 694,500 ORDINARY SHARES OF 5P EACH

MICROGEN PLC 1996 SAVINGS RELATED SHARE OPTION SCHEME - 87,853 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:

102,641,214 ORDINARY SHARES OF 5P EACH


Name of contact: G.E. LIDDLE, COMPANY SECRETARY

Address of contact: FLEET HOUSE, 3 FLEETWOOD PARK, BARLEY WAY, FLEET, HAMPSHIRE, GU51 2QJ

Telephone number of contact: 01252 772 313