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

  Hydrodec Group 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 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): CHANGE TO THE NUMBER OF VOTING RIGHTS IN ISSUE

√

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 Holder:

BNY Norwich Union Nominees Limited   4,307,559*

Chase GA Group Nominees Limited        14,649,874*

CUIM Nominee Limited              4,414,699*

*denotes direct interest   

BNP Paribas - London               1,816,642   

Chase Nominees Limited             5,535,360 

State Street Nominees Limited
           10,852,919

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

   05 January 2009

6. Date on which issuer notified:

    06 January 2009

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

14% to 18% Change at Combined Interest level 

8. Notified details:

A: Voting rights attached to shares

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 viii

Number of shares 

Number of voting rights ix

% of voting rights

Direct

Direct  x

Indirect xi

Direct

Indirect

Ordinary Shares

GB00B02FJF09

41,577,053

41,577,053

  


23,372,132

   


23,372,132

   


18,204,921

   


10.57%

 


8.23%   

B: Financial Instruments

Resulting situation after the triggering transaction xii

Type of financial instrument 

Expiration date xiii

Exercise/ Conversion Period/ Date xiv 

Number of voting rights that may be acquired if the instrument is exercised/ converted. 

% of voting rights

N/A

Total (A+B)

Number of voting rights

% of voting rights

41,577,053

18.80%

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

The voting rights are managed and controlled by Aviva Investors Global Services Limited, with the following chain of controlled undertakings:-

Aviva Investors Global Services Limited:

• Aviva plc (Parent Company)

• Aviva Group Holdings Limited (wholly owned subsidiary of Aviva plc)

• Aviva Investors Holdings Limited (wholly owned subsidiary of Aviva Group Holdings Limited)

• Aviva Investors Global Services Limited (wholly owned subsidiary of Aviva Investors Holdings Limited)

Proxy Voting:

10. Name of the proxy holder:

   See Section 4

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:

Figures are based on a revised total number of voting rights of 221,150,768.

14. Contact name:

   Neil Whittaker

15. Contact telephone number:

   01603 684420