Holding(s) in Company

15 Sep 2008 16:20

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:

Aviva plc & its subsidiaries

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

Registered Holders: BNY Norwich Union Nominees Limited 2,152,019* Chase GA Group Nominees Limited 6,060,241* Chase Nominees Limited 499,123* CUIM Nominee Limited 1,443,603* Chase Nominees Limited 450,710Vidacos Nominees Limited 65,215 * denotes direct interest

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

12 September 2008

6. Date on which issuer notified:

15 September 2008

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

8. Notified details:¢â‚¬¦¢â‚¬¦¢â‚¬¦¢â‚¬¦¢â‚¬¦..

A: Voting rights attached to shares

Class/type of shares if possible Situation previous to the using the ISIN CODE Triggering transaction Number of Number of voting shares Rights Ordinary Shares GB00B07V4P80 10,578,989

Resulting situation after the triggering transaction

Class/type of shares if possible Number of Number of voting % of voting using the ISIN CODE shares rights rights Direct Direct Indirect Direct Indirect Ordinary Shares GB00B07V4P80 10,154,986 10,154,986 515,925 4.78 0.24 B: Financial Instruments

Resulting situation after the triggering transaction

Type of Expiration Exercise/ Number of voting rights that may be % of financial Date Conversion acquired if the instrument is voting instrument Period/ Date exercised/ converted. rights N/A Total (A+B)Number of voting % of voting rights rights 10,670,911 5.02

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: See Section 4

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

N/A

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

N/A 13. Additional information: 14. Contact name:

SILVANA GLIBOTA-VIGO, COMPANY SECRETARIAL ASSISTANT, COOKSON GROUP PLC

15. Contact telephone number:

020 7822 0000