Holding(s) in Company

Costain Group PLC
29 March 2005



Costain Group PLC

('Costain')



Notifiable Interest



Costain announces that it has been notified on 29 March 2005 that Artemis UK
Growth Fund ('Artemis') has increased its holding of ordinary shares in Costain
from 13,200,000 ordinary shares to 15,000,000 ordinary shares. This represents
4.24% of the issued share capital of Costain. The date on which the transaction
was effected is not known.







                                                          29 March 2005



Enquiries:



Costain Group PLC          Tel: [phone]  [e-mail]
Clive L Franks


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