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:

HYDRODEC GROUP PLC

2. Reason for notification (yes/no)

An acquisition or disposal of voting rights

X

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:

AVIVA PLC & ITS SUBSIDIARIES

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

REGISTERED HOLDER:

BNY NORWICH UNION NOMINEES

LIMITED 3,216,939*

CHASE GA GROUP NOMINEES

LIMITED 7,633,182*

CHASE NOMINEES LIMITED 318,160*

CUIM NOMINEE LIMITED 3,820,134*

* DENOTES DIRECT INTEREST

BNP PARIBAS - LONDON 1,816,642

CHASE NOMINEES LIMITED 5,458,213

STATE STREET NOMINEES

LIMITED 11,066,390

VIDACOS NOMINEES LIMITED 632,498

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

25 JUNE 2008

6. Date on which issuer notified:

26 JUNE 2008

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

6% TO 12% CHANGE AT COMBINED INTEREST LEVEL

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

Direct

Number of voting rights

Percentage of voting rights

Direct

Indirect

Direct

Indirect

GB00B07V4P80

10,000,000

10,000,000

14,988,415

14,988,415

18,073,743

5.58%

7.06%

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

33,962,158

12.64%

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

SEE SECTION 4

Proxy Voting:

10. Name of 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 268,718,839

14 Contact name:

NEIL WHITTAKER

15. Contact telephone name:

01603 684420