Note:

As previously reported, the adoption of International Financial Reporting Standards (IFRS) will lead to greater volatility on both underlying and statutory reported earnings due to the effects IFRS has on the accounting treatment of US regulatory assets as compared with UK GAAP and the adoption of International Accounting Standard 39: Financial Instruments, Recognition and Measurement, which the Group adopted with effect from 1 April 2005. While this may cause the reported results for any given period to be more volatile than those reported under UK GAAP, this change in treatment does not impact the performance of the Group or its current or future cash flows.

Cautionary statement

This announcement contains certain statements that are neither reported financial results nor other historical information. These statements are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Because these forward-looking statements are subject to assumptions, risks and uncertainties, actual future results may differ materially from those expressed in or implied by such statements. Many of these assumptions, risks and uncertainties relate to factors that are beyond National Grid’s ability to control or estimate precisely, such as delays in obtaining, or adverse conditions contained in, regulatory approvals, competition and industry restructuring, changes in economic conditions, currency fluctuations, changes in interest and tax rates, changes in energy market prices, changes in historical weather patterns, changes in laws, regulations or regulatory policies, the impact of changes to accounting standards, technological developments, the failure to retain key management, the availability of new acquisition opportunities or the timing and success of future acquisition opportunities. Other factors that could cause actual results to differ materially from those described in this announcement include the ability to obtain, delays in obtaining or adverse conditions contained in regulatory approvals or other consents to acquisitions made by or mergers with National Grid, the ability to integrate these businesses once acquired or merged or to realise the expected synergies from such transactions, the failure for any reason to achieve anticipated reductions in costs or to achieve operational efficiencies, unseasonable weather impacting on demand for electricity and gas, the behaviour of UK electricity market participants on system balancing, the timing of amendments in prices to shippers in the UK gas market, the performance of National Grid’s pension schemes and the regulatory treatment of pension costs and any adverse consequences arising from outages on or otherwise affecting energy networks owned and/or operated by National Grid.

For a more detailed description of these assumptions, risks and uncertainties, together with any other` risk factors, please see National Grid’s filings with and submissions to the US Securities and Exchange Commission (and in particular the “Risk Factors” and “Operating and Financial Review” sections in its most recent annual report on Form 20-F). Recipients are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this announcement. National Grid does not undertake any obligation to release publicly any revisions to these forward-looking statements to reflect events or circumstances after the date of this announcement.