Holding(s) in Company

Cookson Group PLC
19 December 2005

                                  SCHEDULE 10

                   NOTIFICATION OF MAJOR INTERESTS IN SHARES

1) Name of company

COOKSON GROUP PLC

2) Name of shareholder having a major interest

Hermes Focus Asset Management Limited and Hermes SLP Limited

3) Please state whether notification indicates that it is in respect of
holding of the shareholder named in 2 above or in respect of a
non-beneficial interest or in the case of an individual holder if it is a
holding of that person's spouse or children under the age of 18

AS ABOVE

4) Name of the registered holder(s) and, if more than one holder, the
number of shares held by each of them

CHASE NOMINEES LTD (5,357,118 SHARES)

5) Number of shares/amount of stock acquired

N/A

6) Percentage of issued class

N/A

7) Number of shares/amount of stock disposed

NOT DISCLOSED

8) Percentage of issued class

NOT DISCLOSED

9) Class of security

ORDINARY SHARES OF 10 PENCE EACH

10) Date of transaction

15 DECEMBER 2005

11) Date company informed

16 DECEMBER 2005

12) Total holding following this notification

5,357,118 SHARES (HERMES FOCUS ASSET MANAGEMENT LIMITED AND HERMES SLP LIMITED
ONLY)

13) Total percentage holding of issued class following this notification

2.82% (HERMES FOCUS ASSET MANAGEMENT LIMITED AND HERMES SLP LIMITED ONLY)

14) Any additional information

Hermes SLP Limited is only one of the partners of the various partnerships
managed by Hermes Focus Asset Management Limited. Hermes Focus Asset Management
Limited is in turn a subsidiary of BriTel Fund Trustees Limited.

15) Name of contact and telephone number for queries

RACHEL BENJAMIN, COMPANY SECRETARIAL ASSISTANT, COOKSON GROUP PLC - 020 7061
6565

16) Name and signature of authorised company official responsible for
making this notification

RACHEL BENJAMIN, COMPANY SECRETARIAL ASSISTANT, COOKSON GROUP PLC

Date of notification: 19 DECEMBER 2005


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