Blocklisting Interim Review

MICROGEN PLC

28 SEPTEMBER 2012

BLOCK LISTING RETURN

Name of applicant: MICROGEN PLC

Name of scheme: MICROGEN PLC PERFORMANCE SHARE PLAN 2006

MICROGEN PLC COMPANY SHARE OPTION PLAN 2006

Period of return: From: 25 MARCH 2012 To: 24 SEPTEMBER 2012

Balance under scheme from previous return:

MICROGEN PLC PERFORMANCE SHARE PLAN 2006 - 826,732 ORDINARY SHARES OF 5P EACH

MICROGEN PLC COMPANY SHARE OPTION PLAN 2006 - 1,252,052 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:

MICROGEN PLC PERFORMANCE SHARE PLAN 2006 - 0 ORDINARY SHARES OF 5P EACH

MICROGEN PLC COMPANY SHARE OPTION PLAN 2006 - 0 ORDINARY SHARES OF 5P EACH

Number of securities issued/allotted under scheme during period:

MICROGEN PLC PERFORMANCE SHARE PLAN 2006 - 9,167 ORDINARY SHARES OF 5P EACH

MICROGEN PLC COMPANY SHARE OPTION PLAN 2006 -34,971 ORDINARY SHARES OF 5P EACH

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

MICROGEN PLC PERFORMANCE SHARE PLAN 2006 - 817,565 ORDINARY SHARES OF 5P EACH

MICROGEN PLC COMPANY SHARE OPTION PLAN 2006 - 1,217,081 ORDINARY SHARES OF 5P EACH

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

MICROGEN PLC PERFORMANCE SHARE PLAN 2006 - 127,460 ORDINARY SHARES OF 5P EACH - 7 SEPTEMBER 2009

MICROGEN PLC COMPANY SHARE OPTION PLAN 2006 - 142,001 ORDINARY SHARES OF 5P EACH - 7 SEPTEMBER 2009

MICROGEN PLC PERFORMANCE SHARE PLAN 2006 - 650,000 ORDINARY SHARES OF 5P EACH - 24 SEPTEMBER 2010

MICROGEN PLC COMPANY SHARE OPTION PLAN 2006 - 350,000 ORDINARY SHARES OF 5P EACH - 24 SEPTEMBER 2010

MICROGEN PLC PERFORMANCE SHARE PLAN 2006 - 237,517 ORDINARY SHARES OF 5P EACH - 10 OCTOBER 2011

MICROGEN PLC COMPANY SHARE OPTION PLAN 2006 - 184,674 ORDINARY SHARES OF 5P EACH - 10 OCTOBER 2011

MICROGEN PLC PERFORMANCE SHARE PLAN 2006 - 397,991 ORDINARY SHARES OF 5P EACH - 18 OCTOBER 2011

MICROGEN PLC COMPANY SHARE OPTION PLAN 2006 - 1,000,000 ORDINARY SHARES OF 5P EACH - 18 OCTOBER 2011

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

81,569,350 ORDINARY SHARES OF 5P EACH

Name of contact: ANJUM O'NEILL, COMPANY SECRETARY

Address of contact: OLD CHANGE HOUSE, 128 QUEEN VICTORIA STREET, LONDON, EC4V 4BJ

Telephone number of contact: 020 7496 8100

www.microgen.com