Exhibit 23.1




CONSENT ON INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the  incorporation  by reference in  Registration  Statement  Nos.
333-119491,  333-104230,  333-82230,  333-60294, 333-53657 and 333-92003 on Form
S-3  and  Registration  Statement  Nos.  333-119474,  333-53765,  333-40472  and
333-79151  on Form S-8 of our report  dated  February  28, 2005  relating to the
financial  statements and financial  statement  schedule of KeySpan  Corporation
[which report expresses an unqualified  opinion on the financial  statements and
includes an  explanatory  paragraph  related to (i) the adoption of Statement of
Financial  Accounting Standards ("SFAS") No. 142, "Goodwill and Other Intangible
Assets"  discussed in Note 1(G), (ii) the adoption of SFAS No. 148,  "Accounting
for Stock-Based  Compensation-Transaction and Disclosure" in Note 1(N) (iii) the
adoption of SFAS No. 143, "Accounting for Asset Retirement  Obligations" in Note
1(P), (iv) the adoption of FASB Interpretation No. 46 "Consolidation of Variable
Interest  Entities,  an Interpretation of ARB No. 51" (FIN 46) in Note 1(P)] and
our report on management's  report on the effectiveness of internal control over
financial  reporting  appearing  in this  Annual  Report on Form 10-K of KeySpan
Corporation for the year ended December 31, 2004.



/s/ Deloitte & Touche LLP
February 28, 2005
New York, New York