Share of interests

Costain Group PLC
01 February 2007



TR-1(i): NOTIFICATION OF MAJOR INTERESTS IN SHARES



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

Costain Group PLC



2. Reason for the notification (please state Yes/No): (    )



An acquisition or disposal of voting rights: ( Yes  )



An acquisition or disposal of financial instruments which may result in the
acquisition of shares already issued to which voting rights are attached: (    )



An event changing the breakdown of voting rights: (    )



Other (please specify) : (    )



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

Mohd Hussein Ab Hamid



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

UEM Builders Berhad



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

31 January 2007



6. Date on which issuer notified:

31 January 2007



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

35%



8. Notified details:

.................





A: Voting rights attached to shares


Class/type of shares if possible           Situation previous to the Triggering transaction (vi)
using the ISIN CODE
                                  Number of shares                   Number of voting Rights (viii)


GB0002272184                      0                                  0





Resulting situation after the triggering transaction (vii)


Class/type of shares if      Number of shares         Number of voting rights (ix)      % of voting rights
possible using the ISIN CODE
                             Direct                   Direct (x)   Indirect (xi)        Direct      Indirect


                             0                        0            125,354,541          0           35



B: Financial Instruments

Resulting situation after the triggering transaction (xii)


Type of         Expiration Date       Exercise/Conversion       Number of voting rights     % of voting rights
financial       (xiii)                Period/ Date (xiv)        that may be acquired if the
instrument                                                      instrument is exercised/
                                                                converted.








Total (A+B)
Number of voting rights        % of voting rights


125,354,541                    35



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

UEM Builders Berhad owns 93 per cent of Daedalus Projects Limited which holds
125,354,541 shares in Costain Group PLC.  42,500,000 shares are registered in
the name of Daedalus Projects Limited, and a further 82,854,541 shares are
registered in the name of Daedalus Projects Limited's nominee, Rood Nominees
Limited



Proxy Voting:



10. Name of the proxy holder:

Mohd Hussein Ab Hamid



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

125,354,541 (35%)



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

2 February 2007

13. Additional information:

When proxy expires 35% of voting rights will return to UEM Builders Behrad



14. Contact name:

Sharifah Shafiqa Salim



15. Contact telephone number:

0060327189990




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