Notifications of Major Interests in Shares

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:

Costain 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 

No

An event changing the breakdown of voting rights

No

Other (please specify):______________

No

3. Full name of person(s) subject to notification obligation:

Gartmore Investment Limited

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

Fund Managing Co

No. of Shares Held

Issued Share Capital

% of Issued Capital

UK Registered Owner

Fund

Beneficial Owner

Gartmore Fund Managers Limited

7,223,907

1.141%

HSBC Global Custody Nominee UK Ltd.

GCAUTS

Gartmore Fund Managers Ltd A/C 

Gartmore Cautious Managed Funds

Gartmore Fund Managers Limited

4,581,926

0.723%

HSBC Global Custody Nominee UK Ltd

GUKEI

Gartmore Fund Managers A/C Gartmore U.K. Equity Income Fund

Gartmore Fund Managers Limited

8,000,000

1.263%

HSBC Global Custody Nominee UK Ltd.

56690

Gartmore Fund Managers Ltd. A/C Gartmore UK & Irish Smaller Companies

19,805,833

3.127%

Gartmore Investment Limited

1,727,417

0.273%

Gartmore Growth Opportunities

56640

Gartmore Growth Opportunities PLC

Gartmore Investment Limited

523,567

0.083%

Bank of Bermuda Luxembourg

SICAV3

Gartmore SICAV Pan Euro Smaller Companies Fund

Gartmore Investment Limited

2,008,513

0.317%

Vidacos Nominees Ltd A/C 2303

VOLANT

The Alphagen Volantis Fund Limited

Gartmore Investment Limited

7,082,833

1.118%

Nortrust Nominees Limited

54550

Strathclyde Pension Fund

11,342,330

1.791%

31,148,163

633,366,063

4.918%

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

3 February 2009

6. Date on which issuer notified:

4 February 2009

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

5%

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

GB0002272184

50,117,835

50,117,835

31,148,163

31,148,163

4.918%

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

Total (A+B)

Number of voting rights

Percentage of voting rights

31,148,163

4.918%

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:

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:

All shares are held indirectly.

All figures are based on the Company's issued share capital of 633,366,063 as provided by Exshare

Email contact [email protected]

14 Contact name:

RDU

15. Contact telephone number:

020 7782 2000