Holding(s) in Company

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

Severn Trent Plc

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

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 the notification obligation:

Pictet Asset Management SA

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

See Above

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

11th March 2011

6. Date on which issuer notified:

15th March 2011

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 using the ISIN CODE

Situation previous to the Triggering transaction

Resulting situation after the triggering transaction

Number of Voting Rights

Number of shares

Number of voting rights

% of voting rights

Direct

Indirect

Direct

Indirect

Ordinary Shares

GB0002504529

11,962,479

11,962,479

 0

0

11,804,658

0

4.98%

B: Financial Instruments

Resulting situation after the triggering transaction

Type of financial instrument

Expiration date

Exercise/ Conversion Period/ Date

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

% of voting rights

N/A

N/A

N/A

N/A

N/A

Total (A+B)

Number of voting rights

% of voting rights

11,804,658

4.98%

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

No controlled undertakings hold greater than 3% of the voting capital of Severn Trent Plc.

Proxy Voting:

10. Name of the proxy holder:

Pictet Asset Management SA

11. Number of voting rights proxy holder will cease to hold:

Not Applicable

12. Date on which proxy holder will cease to hold voting rights:

Not Applicable

13. Additional information:

Not Applicable

14. Contact name:

Richard Brierley

15. Contact telephone number:

0247 771 5000