Exhibit 4.2

Dated
30 July 2004



(1) INTERNATIONAL POWER PLC

and

(2) CAZENOVE & CO. LTD

and

(3) MORGAN STANLEY SECURITIES LIMITED

and

(4) MORGAN STANLEY & CO. INTERNATIONAL LIMITED



RIGHTS ISSUE UNDERWRITING AGREEMENT



Linklaters

One Silk Street
London EC2Y 8HQ

Telephone
(44-20) 7456 2000
Facsimile (44-20) 7456 2222

Ref:
BR/RZZC

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THIS AGREEMENTis made on 30 July 2004

BETWEEN:

WHEREAS:

IT IS AGREEDas follows:

1          Interpretation



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2          Conditions

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3          The Rights Issue



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10        Indemnity



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11        Termination



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12        Withdrawal of Approval

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13        General

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14        Notices



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15        Governing Law and Submission to Jurisdiction

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In witnesswhereof this Agreement has been entered into on the date stated at the beginning.

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Schedule 1    Documents in the agreed form

Document



ANP
Announcement

Results
Announcement

Acquisition
Announcement

Rights
Issue Announcement

Announcement
Board Resolutions

Letter
to QIBs

Sub-underwriting
Letter

Announcement
Verification Materials

Analysts
Presentation

Directors'
Undertaking

CREST
Confirmation Letter

Reporting
Accountants' engagement letter in relation to the Rights Issue and the acquisition

Auditors
engagement letter relating to the Rights Issue and the acquisition

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Schedule 2Documents to be delivered pursuant to Clause 2

Part A

Save to the extent that the same have been delivered to the Underwriters prior to the date of this Agreement, immediately after the execution of this Agreement
and, in any event, before the Announcements is released, the Company shall deliver to the Underwriters:

Part B

Save to the extent that the same have been delivered to the Underwriters prior to such date, the Company shall deliver to the Underwriters prior to
7.00 a.m. on the Posting Date:

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Part C

On the Posting Date before despatching the Prospectus in accordance with Clause 3.6, the Company shall deliver to the Underwriters:

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Part D

Prior to Admission, the Company shall deliver to the Underwriters certified copies of the Participating Securities application forms in respect of the
Nil-paid Rights and the Fully-paid Rights given by the Company to CREST.

Part E

On the day of Admission, the Company shall deliver to the Underwriters:

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Schedule 3    [Letterhead of the Company]

To:
[The Underwriters and the Joint Sponsors]
[Address]

[DATE]

Dear
Sirs

Proposed Rights Issue of        Ordinary Shares of        p each (the "Rights Issue")

We refer to the proposed Rights Issue and the Underwriting Agreement relating thereto dated        (the
"Underwriting Agreement"). Words and expressions defined in the Underwriting Agreement have the same meanings herein.

We
confirm that:

Yours
faithfully

|Director
for and on behalf of
International Power plc | 
|----------------------------------------------------- | 

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|SIGNED by
for and on behalf ofInternational Power plcin the presence of:                    | }
|------------------------------------------------------------------------------------------- | -
|SIGNED by
for and on behalf ofCazenove & Co. Ltdin the presence of:                         | }
|SIGNED by
for and on behalf ofMorgan Stanley & Co. International Limitedin the presence of: | }
|SIGNED by
for and on behalf ofMorgan Stanley Securities Limitedin the presence of:          | }

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Dated    August 2004



(1) INTERNATIONAL POWER PLC

and

(2) CAZENOVE & CO. LTD

and

(3) MORGAN STANLEY SECURITIES LIMITED

and

(4) MORGAN STANLEY & CO. INTERNATIONAL LIMITED



SUPPLEMENTAL AGREEMENT TO THE RIGHTS ISSUE UNDERWRITING AGREEMENT



Linklaters

One Silk Street
London EC2Y 8HQ

Telephone
(44-20) 7456 2000
Facsimile (44-20) 7456 2222

Ref:
BR/RZZC

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THIS AGREEMENTis made on    August 2004

BETWEEN:

WHEREAS:

The Parties are each party to a rights issue underwriting agreement dated 30 July 2004 (the "Rights Issue Underwriting
Agreement"). The Parties wish to amend the Rights Issue Underwriting Agreement on the terms set out in this Agreement.



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2          General

3          Governing Law and Submission to Jurisdiction

In witnesswhereof this Agreement has been entered into on the date stated at the beginning.

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|SIGNED by
for and on behalf ofInternational Power plcin the presence of:                    | }
|------------------------------------------------------------------------------------------- | -
|SIGNED by
for and on behalf ofCazenove & Co. Ltdin the presence of:                         | }
|SIGNED by
for and on behalf ofMorgan Stanley & Co. International Limitedin the presence of: | }
|SIGNED by
for and on behalf ofMorgan Stanley Securities Limitedin the presence of:          | }

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