TR1 Notification of Major Interest in shares

For filings with the FSA include the annex

For filings with issuer exclude the annex

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARESⁱ

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

United Utilites 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 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):

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

BlackRock, Inc.

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

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

11^th January 2010

6. Date on which issuer notified:

12^th January 2010

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

Holding has gone above 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

GB00B39J2M42

N/A

N/A

N/A

N/A

33,650,655

N/A

4.94%

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}

CFD

N/A

N/A

N/A

441,012

Nominal

Delta

0.06%

0.06%

Total (A+B+C)

Number of voting rights

Percentage of voting rights

34,091,667

5.00%

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

BlackRock Investment Management (UK) Limited - 34,091,667 (5.00%)

Proxy Voting:

10. Name of the 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:

BlackRock Compliance Disclosures Team

14. Contact name:

Stuart Watchorn

15. Contact telephone number:

020 7743 5741; stuart.watchorn@blackrock.com

Note: Annex should only be submitted to the FSA not the issuer

Annex: Notification of major interests in shares^xxii

A: Identity of the persons or legal entity subject to the notification obligation

Full name

(including legal form of legal entities)

BlackRock, Inc.

Contact address

(registered office for legal entities)

33 King William Street, London, EC4R 9AS

Phone number & email

020 7743 5741  stuart.watchorn@blackrock.com

Other useful information

(at least legal representative for legal persons)

Stuart Watchorn

B: Identity of the notifier, if applicable

Full name

Contact address

Phone number & email

Other useful information

(e.g. functional relationship with the person or legal entity subject to the notification obligation)

C: Additional information

For notes on how to complete form TR-1 please see the FSA website.