Notification of Shares

Costain Group PLC
07 November 2007


TR-1: Notifications of Major Interests in Shares


Costain Group PLC

1. Identity of the issuer or the underlying issuer of existing
shares to which voting rights are attached:


2. Reason for notification (yes/no)
                                                                                            

An acquisition or disposal of voting rights                                  Yes
                                                                                            
An acquisition or disposal of financial instruments which may result in the   No
acquisition of shares already issued to which voting rights are attached        
                                                                                
An event changing the breakdown of voting rights                              No
                                                                                            

Other placing                                                                Yes

                                                         

3. Full name of person(s) subject to notification
obligation:

Gartmore Investment Limited
                                                         

4. Full name of shareholder(s) (if different from 3):    

HSBC Global Custody Nominee UK Ltd                                          
HSBC Global Investor Services
BNY GIL CLT A/C NOMS LTD A/C NWSC
BNY GIL CLT A/C NOMS LTD A/C LST
Bank of Bermuda Luxembourg
Vidacos Nominees Ltd A/C 2303
Nortrust Nominees Limited


                                                         

5. Date of transaction (and date on which the threshold
is crossed or reached if different):

1st November 2007
                                                         

6. Date on which issuer notified:

2nd November 2007
                                                         

7. Threshold(s) that is/are crossed or reached:

8%




8: Notified Details
A: Voting rights attached to shares


Class/type of    Situation previous to    Resulting situation after the triggering transaction
shares           the triggering
                 transaction
If possible use  Number of Number of      Number of    Number of voting rights     Percentage of voting
ISIN code        shares    voting rights  shares                                   rights



                                                       Direct      Indirect        Direct    Indirect

GB0002272184     Below       Below        50,117,835               50,117,835                8.017%
                 5%          5%






B: Financial Instruments


Resulting situation after the triggering transaction


Type of financial    Expiration date      Exercise/ conversion No. of voting rights  Percentage of voting
instrument                                period/date          that may be acquired  rights
                                                               (if the instrument
                                                               exercised/converted)

Total (A+B)


Number of voting rights                              Percentage of voting rights

50,117,835                                           8.017%



9. Chain of controlled undertakings through which the voting rights and /or the
financial instruments are effectively held, if applicable:


Proxy Voting:


10. Name of proxy holder:


11. Number of voting rights proxy holder will cease
to hold:


12. Date on which proxy holder will cease to hold
voting rights:




13. Additional information:                           All shares are held indirectly



                                                      All figures are based on the companies issued share
                                                      capital of 625,154,761 as provided by Exshare



                                                      Email contact [e-mail]
14 Contact name:                                      RDU


15. Contact telephone name:                           0207 782 2000





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