Cookson Group plc : Holding(s) in Company

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: Governance for Owners LLP

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

Governance for Owners European Focus Fund 1

Governance for Owners European Focus Fund 2

Governance for Owners European Focus Fund 3

Governance for Owners European Focus Fund 4

Governance for Owners European Focus Fund 5

5. Date of the transaction (and date on which the threshold is crossed or reached if different): 13th January 2012

6. Date on which issuer notified: 13th January 2012

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

8. Notified details:

A: Voting rights attached to shares

Class/type of shares if possible using the ISIN CODE	Situation previous to the Triggering transaction
Ordinary Shares GB00B3WK5475	Number of shares 11,041,051	Number of voting Rights 11,041,051

Resulting situation after the triggering transaction

Class/type of shares if possible using the ISIN CODE	Number of shares	Number of voting rights		% of voting rights
Ordinary Shares GB00B3WK5475	11,199,895	Direct 11,199,895	Indirect	Direct 4.05%	Indirect

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

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

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

Resulting situation after the triggering transaction

Type of financial instrument	Exercise price	Expiration date	Exercise/Conversion period	Number of voting rights instrument refers to	% of voting rights
					Nominal	Delta

Total (A+B+C)

Number of voting rights 11,199,895	% of voting rights 4.05%

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

See section 4

Proxy Voting:

10. Name of the proxy holder:

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

12.

13. Additional information:

14. Contact name:

RACHEL FELL, DEPUTY SECRETARY, COOKSON GROUP PLC

15. Contact telephone number:

+ 44 (0)20 7822 0000