.
TR-1: NOTIFICATION OF MAJOR INTERESTS IN SHARES

1. Identity of the issuer or the underlying issuer of existing shares to which
voting rights are attached:
COOKSON 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:
Adage Capital Partners GP LLC

4. Full name of shareholder(s) (if different from 3.):
JP Morgan Custodial Trust Company and Morgan Stanley & Co.

5. Date of the transaction (and date on which the threshold is crossed or
reached if different):
23 February 2010

6. Date on which issuer notified:
25 February 2010

7. Threshold(s) that is/are crossed or reached:
4%

8. Notified details:
#####..

A: Voting rights attached to shares

Class/type of shares  Situation previous to the Triggering transaction
if possible using the
ISIN CODE

                      Number of shares       Number of voting Rights


Ordinary Shares

GB00B3WK5475          10,595,982               10,595,982


Resulting situation after the triggering transaction

Class/type of shares  Number of shares   Number of voting rights     % of voting rights
if possible using the
ISIN CODE

                                         Direct     Indirect         Direct    Indirect


Ordinary Shares

GB00B3WK5475          11,295,982         11,295,982                  4.08



B: Financial Instruments
Resulting situation after the triggering transaction

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

None



 C:Financial Instruments with similar economic effect to Qualifying Financial
instruments

Resulting situation after the triggering transaction

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

                                     None


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


11,295,982           4.08


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

JP Morgan Custodial Trust Company and Morgan Stanley & Co. are the custodians
of the shares held by Adage Custodial Partners GP LLC.

Proxy Voting:

10. Name of the 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:


14. Contact name:
RACHEL FELL, DEPUTY SECRETARY, COOKSON GROUP PLC

15. Contact telephone number:
+  44 (0) 20 7822 0000

END