Holding(s) in Company

1. Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached: ii

Atkins (WS) plc

2. Reason for the notification (please tick the appropriate box or boxes):

An acquisition or disposal of voting rights

An acquisition or disposal of qualifying financial instruments which may result in the acquisition of shares already issued to which voting rights are attached

An acquisition or disposal of instruments with similar economic effect to qualifying financial instruments

An event changing the breakdown of voting rights

Other (please specify):

Acquisition of Columbia Management Investment Advisors LLC and Columbia Wanger Asset Management by Ameriprise Financial, Inc., 1099 Ameriprise Financial Center, Minneapolis, MN 55474, USA

Y

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

Ameriprise Financial, Inc. and its group

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

See additional information under 13

5. Date of the transaction and date on which the threshold is crossed or reached: v

1 May 2010

6. Date on which issuer notified:

3 May 2010

* received by fax by WS Atkins plc on 4 May 2010

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

Above the threshold of 5%

8. Notified details:

A: Voting rights attached to shares viii, ix

Class/type of shares

if possible using the 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

% of voting rights x

Direct

Direct xi

Indirect xii

Direct

Indirect

Ordinary Shares

GB0000608009

N/A

N/A

35,300

35,300

5,094,617

0.035%

5.089%

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financial instrument

Expiration date xiii

Exercise/ Conversion Period xiv

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 xv, xvi

Resulting situation after the triggering transaction

Type of financial instrument

Exercise price

Expiration date xvii

Exercise/ Conversion period xviii

Number of voting rights instrument refers to

% of voting rights xix, xx

Nominal

Delta

Total (A+B+C)

Number of voting rights

Percentage of voting rights

5,129,917

5.124%

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

Ameriprise Financial, Inc., which through intermediate holding companies controls the voting rights of Columbia Management Investment Advisers, Columbia Wanger Asset Management, Threadneedle Management Luxembourg S.A. and Threadneedle Asset Management Holdings Ltd, which itself controls the voting rights of Threadneedle Asset Management Ltd, Threadneedle International Ltd and Threadneedle Pensions Ltd.

Proxy Voting:

10. Name of the 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:

Registered Owner

14. Contact name:

Company Secretary, Threadneedle Group

15. Contact telephone number:

+44 (0)20 7434 5000