Holding(s) in Company

TR-1: Notifications 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 notification (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 notification obligation:

Legal & General Group Plc (L&G)

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

Legal & General Assurance (Pensions Management) Limited (PMC)

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

1 December 2008

6. Date on which issuer notified:

3 December 2008

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

From 3% - 4% (L&G)

8: Notified Details

A: Voting rights attached to shares

Class/type of shares

If possible use ISIN code

Situation previous to the triggering transaction

Resulting situation after the triggering transaction

Number of shares

Number of voting rights

Number of shares

Number of voting rights

Percentage of voting rights

Direct

Indirect

Direct

Indirect

Ordinary Shares

ORD

GBP 0.10

8,492,127

8,492,127

8,715,515

8,715,515

4.09

B: Financial Instruments

Resulting situation after the triggering transaction

Type of financial instrument

Expiration date

Exercise/ conversion period/date 

No. of voting rights that may be acquired (if the instrument exercised/converted)

Percentage of voting rights

N/A

Total (A+B)

Number of voting rights

Percentage of voting rights

8,715,515

4.09

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

Proxy Voting:

10. Name of proxy holder:

N/A

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:

Rachel Fell, Deputy Secretary Cookson Group plc

15. Contact telephone number:

Tel: + 44 (0)20 7822 0062