Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the  incorporation  by reference  in  Registration  Statement  No.
333-119474  and No.  333-40472  of KeySpan  Corporation  on each Form S-8 of our
report dated June 27, 2007,  appearing in this Annual Report on Form 11-K of the
KeySpan  Energy 401(k) Plan for Union  Employees for the year ended December 31,
2006.

 /s/ Deloitte & Touche LLP
New York, New York


June 27, 2007













                                       17