##### Table of Contents

 

 

**SECURITIES AND EXCHANGECOMMISSION**

**Washington, D.C. 20549**

**FORM 20-F**

(Mark One) 

**Commission file number: 001-14958**

**NATIONAL GRID PLC**

*(Exact name of Registrant as specified in its charter)*

*England and Wales*

*(Jurisdiction of incorporation or organization)*

*1-3 Strand, London WC2N 5EH, England*

*(Address of principal executive offices)*

**Helen Mahy**

**011 44 20 7004 3000**

**Facsimile No. 011 44 20 7004 3004**

**Company Secretary and GeneralCounsel**

**National Grid plc**

**1-3 Strand London WC2N 5EH, England**

*(Name, Telephone, E-mail and/orFacsimile number and Address of Company Contact Person)*

**Securities registered or to be registered pursuant toSection 12(b) of the Securities Exchange Act of 1934:**

 

 

 

 

**Securities registered or to be registered pursuant to Section 12(g) of the Securities Exchange Act of 1934:** None.

**Securities for which there is a reporting obligation pursuant to Section 15(d) of the Securities Exchange Act of1934: **None. 

The number of outstanding shares of each of the issuer’s classes of capital or common stock as ofMarch 31, 2012 was 

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined inRule 405 of the Securities Act: Yes þ No  ̈o 

If this report is an annual or transition report, indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Securities Exchange Act of1934.  Yes  ̈  No þ

Note — Checking the box above will not relieve any registrant required to file reports pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 from their obligations under thoseSections. 

Indicate by check mark whether the registrant (1) has filed all reports required to be filedby Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for thepast 90 days:  Yes þ  No  ̈

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate website, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post suchfiles):  Yes  ̈  No  ̈

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer. See definition of “accelerated filer” and “large acceleratedfiler” in Rule 12b-2 of the Exchange Act. 

Indicate by check mark which basis of accounting the registrant has used to prepare thefinancial statements included in this filing: 

U.S. GAAP  ̈    International Financial Reporting Standards as issued by the International Accounting Standards Board þ    Other  ̈

If “Other” has been checked in response to the previousquestion, indicate by check mark which financial statement item the registrant has elected to follow.  Item 17  ̈    Item 18  ̈

If this is an annual report, indicate by check mark whether theregistrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).  Yes  ̈ No þ

This constitutes the annual report on Form 20-F of National Grid Plc (the “Company”) in accordance with the requirements of theUS Securities and Exchange Commission (the “SEC”) for the year ended 31 March 2012 and is dated 12 June 2012. Details of events occurring subsequent to the approval of the annual report on 16 May 2012 are summarised in thesection titled “Further Information”. The content of the Group’s website (www.nationalgrid.com/uk) should not be considered to form part of this annual report on Form 20-F. 

 

 

 

Table of Contents
**Form 20-F Cross Reference Table**

 

**Item**
  **Form 20-F caption**  **Location in the document**  ** ****Page  ****  **
**1**
  
**Identity of directors, senior management and advisors**
  
Not applicable
   –      
**2**
  
**Offer statistics and expected timetable**
  
Not applicable
   –      
**3**
  
**Key Information**
      
3A Selected financial data
  
“Summary consolidated financial information”
   194-195      
“Financial performance”
   56-63      
“Additional disclosures—Exchange rates”
   189            
“Exchange Rates”