**Exhibit 4(a)(i)**

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21 November 2002

|                       | Ref: Agency/CMTodd         |
|----------------------------|----------------------------|
|                       | Direct Line: 020 7992 2047 |
|                       | Fax No: 020 7991 4351      |
| Also By Fax: 020 7312 5651 |                       |
| National Grid Transco plc  |                       |
| 15 Marylebone Road         |                       |
| London NW1 5JD             |                       |

For the attention of Martin O'Donovan, Group Treasurer

 Dear Sirs

**NATIONAL GRID TRANSCO PLC (formerly National  Grid Group plc) (the “Company”)    US$2.3bn Revolving Credit Facility 22 November 2001 (the “Facility  Agreement”)**

We refer to the Facility Agreement. Defined terms  used in the Facility Agreement shall have the same meaning when used in their  capitalised form in this letter. 

In accordance with clause 5.7 of the Facility  Agreement, the Company requested an extension to the Facility A Availability  Period for a period which is not later than 364 days after the original expiry  date (the “Extended Date”). 

**EXTENSION**

We have now received responses from each of the  Revolving Facility Banks and can confirm that the Facility A Commitments shall  be extended in the amount of US$1,526,556,521.74 until the Extended Date, 20  November 2003. 

**COMMITMENTS**

With effect from 21 November 2002: 

| • | The Facility A Commitments of BT Holdings      (New York), Inc, Fleet National Bank, Landesbank Hessen-Thuringen Girozentrale,      Ireland, ANZ Banking Group Limited, Banco Santander Central Hispano, S.A.      and Garras Bank – Naspa, Dublin shall be reduced to zero; and |
|---------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|    |                                                                                                                                                                                                                                                                                   |
| • | In order to record the Commitments of the      Banks that have agreed to extend, Part I of Schedule 1 (The Banks) shall      be deleted and the schedule to this letter shall be inserted as Schedule      1 to the Facility Agreement.                                                |

**HSBC Investment Bank plc**Debt Finance, Support & Agency Services, Level 17, 8  Canada Square, London E14 5HQTel: +44 20 7991 8888 Fax: +44 20 7991  4347/4351*Registered Office: 8 Canada Square, London E14 5HQ  Incorporated in England with limited liability. Registered number 976092   Regulated by the Financial Services Authority. Member of the London Stock Exchange.*

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Cont./221 November 2002   National Grid Transco plc

 

We will continue to advise you of any further  changes to the Commitments of the Banks as and when they may occur.

**FEES**

In accordance with the Facility Agreement, the  Company has arranged to remit to the Agent for the account of the Banks an extension  fee calculated at the rate of 0.05 per cent flat on the aggregate Original Dollar  Amount of the Facility A Commitments of those Banks who have agreed to extend  the Facility A Availability Period.

**CONTINUING VALIDITY**

To the extent that the Facility Agreement has  not been expressly amended by the terms of this letter, the Facility Agreement  shall continue in full force and effect in accordance with its terms.

**GOVERNING LAW**

This letter shall be governed by, and construed  in accordance with, English law.

Please signify your agreement to the terms of  this letter by signing where indicated below.

Yours faithfully 

for and on behalf of   HSBC Investment Bank Plc (as Facility Agent, for and on behalf of the Banks)  

We hereby agree to the above.

for and on behalf of   National Grid Transco plc(on behalf of itself, each Borrower and Guarantor)

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**Schedule 1**

**The Banks**

**Part I**

**Facility A Banks and Commitments**

| **Bank**                                    | **Facility A Commitment US$** | **New % Share of Commitment** |
|---------------------------------------------|-------------------------------|-------------------------------|
|                                        |                          |                          |
| ABN Amro Bank N.V.                          | 85,000,000.00                 | 5.57                          |
| Bank of America N.A                         | 70,217,391.30                 | 4.60                          |
| The Bank of Tokyo Mitsubishi, Ltd           | 110,869,565.22                | 7.26                          |
| Barclays Bank plc                           | 44,347,826.08                 | 2.91                          |
| Bayerische Landesbank Girozentrale, London  | 110,869,565.22                | 7.26                          |
| Citibank, N.A.                              | 65,000,000.00                 | 4.26                          |
| Dresdner Bank AG London                     | 59,130,434.78                 | 3.87                          |
| HSBC Bank plc                               | 85,000,000.00                 | 5.57                          |
| JP Morgan Chase Bank                        | 65,000,000.00                 | 4.26                          |
| TD Bank Europe Limited                      | 55,000,000.00                 | 3.60                          |
| BBVA Ireland plc                            | 49,373,913.04                 | 3.23                          |
| The Bank of New York                        | 49,373,913.04                 | 3.23                          |
| Commerzbank Aktiengesellschaft, London      | 49,373,913.04                 | 3.23                          |
| Deutsche Bank AG London                     | 49,373,913.04                 | 3.23                          |
| ING Bank N.V., London Branch                | 49,373,913.04                 | 3.23                          |
| Landesbank Baden-Wurttemberg                | 49,373,913.04                 | 3.23                          |
| National Australia Bank Limited             | 49,373,913.04                 | 3.23                          |
| Royal Bank of Canada Europe Limited         | 49,373,913.04                 | 3.23                          |
| The Royal Bank of Scotland plc              | 49,373,913.04                 | 3.23                          |
| Scotiabank Europe plc                       |  34,373,913.04           | 2.25                          |
| RBS International Limited (from 15/11/2002) | 15,000,000.00                 | 0.98                          |
| Societe Generale                            | 49,373,913.04                 | 3.23                          |
| Westdeutsche Landesbank Girozentrale        | 49,373,913.04                 | 3.23                          |
| Mellon Bank, N.A.                           | 27,347,826.09                 | 1.79                          |
| Sumitomo Mitsui Banking Corporation (SMBC)  | 27,347,826.09                 | 1.79                          |
| National Westminster Bank plc               | 10,000,000.00                 | 0.66                          |
| Bank of China, London Branch                | 29,565,217.40                 | 1.94                          |
| Bank of China, Luxembourg                   | 40,000,000.00                 | 2.62                          |
| Mizuho Corporate Bank Ltd, London           | 49,373,913.08                 | 3.23                          |
|                                        | **US$1,526,556,521.74**       | **100%**                      |

 

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