TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARES

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

International Power Plc

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

An acquisition or disposal of voting rights

Yes

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: 

Invesco Limited

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

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

22 December 2009

6. Date on which issuer notified:

24 December 2009

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

5%, 10%

8. Notified details:

A: Voting rights attached to shares 

Class/type of
shares

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

Direct

Indirect

Direct

Indirect

ORD 50p Shares

GB006320161

128,750,486

128,750,486

153,127,480

10.05%

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financial
instrument

Expiration
date

Exercise/ 
Conversion Period

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 

Resulting situation after the triggering transaction

Type of financial
instrument

Exercise price

Expiration date 

Exercise/
Conversion period 

Number of voting rights instrument refers to

% of voting rights 

Nominal

Delta

Total (A+B+C)

Number of voting rights

Percentage of voting rights

153,127,480

10.05%

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

Bank of Ireland (Dublin) - 482,509

Bank of New York - 97,462,534

JP Morgan Chase - 310,502

HSBC - 1,665,733

Mellon Bank (Pittsburgh) - 676,542

State Street (London) - 14,506,287

Northern Trust Company (London) - 997,763

PowerShares - 47,488

Invesco AIM - 25,765,265

Other - 11,212,857

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:

14. Contact name:

Carolyn Gibson

15. Contact telephone number:

020 7320 8600