Voting Rights

Costain Group PLC
21 December 2006

Costain Group PLC

('Costain' or the 'Company')

Voting Rights and Capital



In conformity with the Transparency Directive's transitional provision 6 we
would like to notify the market of the following:



The Company's capital consists of 357,231,292 ordinary shares of 5p each with
voting rights ('Ordinary Shares'). The Company does not hold any Ordinary Shares
in Treasury.



The above figure 357,231,292 may be used by shareholders as the denominator for
the calculations by which they will determine if they are required to notify
their interest in, or a change to their interest in, Costain under the FSA's
Disclosure and Transparency Rules.


                                                                21 December 2006

Enquiries:




Costain Group PLC               Tel: [phone]
Clive L Franks

College Hill                    Tel. [phone]
Mark Garraway
Matthew Gregorowski
















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