NGG

National Grid plc Form 6-K Summary

Business Context and Reporting Period

This Form 6-K, dated March 29, 2007, serves as a report of foreign issuer for National Grid plc. It aggregates announcements made to the London Stock Exchange during March 2007, including a close period trading update for the twelve months ending March 31, 2007. The filing details debt issuances, share repurchases, director interests, and forward-looking financial guidance ahead of the preliminary results announcement scheduled for May 17, 2007.

Key Financial Metrics and Capital Activities

Debt Issuances (Euro Medium Term Note Programme):

• March 19: Issued EUR 100,000,000 at 3.25% due 2009.
• March 21: Issued EUR 250,000,000 at 4.125% due 2013.
• March 28: Issued EUR 50,000,000 at 4.255% due 2008.
• March 28: Issued GBP 50,000,000 at 5.25% due 2011.

Share Repurchases:

The company completed its share buyback programme relating to US stranded assets cash flows. Throughout March 2007, the company purchased and cancelled shares daily. The weighted average number of shares for the year is forecast to be approximately 2,719 million. As of March 22, 2007, the number of ordinary shares in issue was 2,701,028,562.

Historical Operating Profit (2005/06):

Material Changes and Outlook

Trading Update for Year Ending March 31, 2007:

• Profit and Earnings: Operating profit is expected to be ahead of the prior year on a constant currency basis. Earnings per share are also expected to grow, driven by lower financing costs and an effective tax rate of approximately 32%.
• Revenue Drivers: Higher revenues are anticipated, primarily due to increased allowed revenues in UK electricity transmission and a recovery from the New York deferral account.
• Headwinds: Revenue growth is expected to be partially offset by timing impacts, including under-recovery in UK transmission, under-recovery in UK gas distribution due to a warm winter, and higher storm costs in the US. US electricity distribution revenue is expected to be lower due to weather closer to the seasonal norm.
• Costs: Controllable operating costs are anticipated to be higher, driven by increased workload in the UK and US.
• Capital Expenditure and Debt: Capital expenditure is forecast at approximately £2.3 billion. Closing net debt is expected to be around £11.8 billion, excluding certain mark-to-market effects.

Risks, Contingencies, and Unusual Items

The filing includes a comprehensive cautionary statement regarding forward-looking statements. Key risks identified include:

• Regulatory approvals and contractual consents, specifically regarding the proposed acquisition of KeySpan.
• Unseasonable weather affecting demand for electricity and gas.
• Currency fluctuations, changes in interest and tax rates, and energy market prices.
• Integration risks associated with announced acquisitions and the ability to realize synergies.
• Performance of pension schemes and regulatory treatment of pension costs.
• Operational outages affecting energy networks.

Shareholder Activity: Fidelity International Limited and subsidiaries notified an interest of 3.06% in the company's ordinary shares as of March 15, 2007.

Investor Verification Checklist

• Verify the final preliminary results announced on May 17, 2007, to confirm if operating profit and earnings per share met the "ahead of last year" guidance.
• Confirm the actual closing net debt figure against the forecast of £11.8 billion, noting the exclusion of mark-to-market effects.
• Monitor the status and regulatory approval of the proposed KeySpan acquisition mentioned in the risk factors.
• Review the impact of the warm UK winter on gas distribution revenue recovery in the final audited results.
• Check the final weighted average share count against the forecast of 2,719 million to validate earnings per share calculations.