Supplementary consideration shares

Avacta Group plc                                

                Admission of Supplementary Consideration Shares                

Further to the announcement of 8 August 2006, Avacta Group plc ("Avacta" or the
"Company") is pleased to announce the acquisition of the Avacta Option Shares
issued upon the exercise of the Avacta Options pursuant to the Supplemental
Acquisition Agreement.

The consideration for the Avacta Option Shares has been satisfied by the
allotment and issue of 24,469,898 new Ordinary Shares of the Company which have
been admitted to trading on AIM today. The new Ordinary Shares represent
approximately 3.66% of the enlarged issued share capital of the Company which
now totals 669,327,344 Ordinary Shares.

Following Admission, Daron Lee no longer has a notifiable interest in the
Company and the interests of certain directors are as follows:

Director                   Number of Ordinary Shares     Percentage of Enlarged
                                                                  Share Capital
                                                                               
Professor Alastair Smith                  49,217,468                       7.35
                                                                               
Simon Webster                             48,624,258                       7.26
                                                                               
Kurt Baldwin                              48,624,258                       7.26

All terms used in this announcement are defined as set out in the Admission
Document dated 13 July 2006.

                                                                  9 August 2006

Enquiries:

Avacta Group plc                              Tel: [phone]               
                                                                               
Alastair Smith, Chief Executive                                                
                                                                               
WH Ireland Limited                            Tel: [phone]               
                                                                               
David Youngman, Director, Corporate Finance                                    
                                                                               
Nexus Financial Ltd                           Tel: [phone]               
                                                                               
Nicholas Nelson, Director                     [e-mail]