Exhibit 99.1

nationalgrid                                                            KEYSPAN

                   NATIONAL GRID / KEYSPAN ANNOUNCE MANAGEMENT
                               AGREEMENT WITH LIPA

     - Affirms merger is in best interests of Long Island electric customers

                - Provides significant long-term energy benefits

             - Enhances environmental and energy efficiency programs



Hicksville, NY (March 23, 2007) - National Grid (LSE: NG. NYSE: NGG) and KeySpan
Corp. (NYSE: KSE) today announced an amended and enhanced  seven-year  agreement
with the Long  Island  Power  Authority  ("LIPA")  to  operate  the  electricity
transmission and distribution system on Long Island. This agreement affirms that
the National Grid/KeySpan merger is in the best interest of Long Island electric
customers,  and is also an  important  step in the merger of  National  Grid and
KeySpan, targeted for completion in mid-2007.

Under the  Management  Services  Agreement,  which becomes  effective  after the
merger and runs through 2013,  National  Grid/KeySpan  will provide  significant
benefits to LIPA's 1.1 million customers including:

o    $91  million of  synergy  savings  for Long  Island's  electric  customers,
     generated  by the  National  Grid/KeySpan  merger  through  the term of the
     Management  Services  Agreement - a significant  share of the proposed $500
     million  permanent  synergies  for  customers in New York over the next ten
     years

o    $100  million  investment  in  efficiency  and  environmental  upgrades  at
     Northport and Port Jefferson power plants

     o    LIPA customers will not face additional  charges as costs of the power
          plant  modernizations  are  expected  to be fully  offset  by fuel and
          emissions cost savings

     o    In addition  National  Grid will  perform a detailed  Northport  Plant
          engineering and economics repowering study

o    $12 million  investment in a joint energy efficiency  program with LIPA for
     electric and gas customers on Long Island

o    LIPA  now  having  options  to  purchase  the  Wading  River  and  Shoreham
     generating  stations,  which join existing  options on the E.F. Barrett and
     Far Rockaway plants, for the purpose of repowering

o    Retention of a strong  on-Island field workforce to maintain the high level
     of reliability that Long Island customers expect

o    Commitment to leverage National Grid's international engineering experience
     in  electric  system  management  and energy  efficiency  programs  for the
     benefit of LIPA customers

These amendments expand the Management  Services Agreement  contract,  agreed by
KeySpan in December 2005, which included the payment of $120 million in cash and
credits,  and  savings  of $34  million  per annum  phased in over a  three-year
period.

"I'm very pleased that LIPA and National  Grid/KeySpan have been able to address
critical  energy  issues and  challenges  that we face today - cost  management,
protecting the  environment  and enhancing our energy future for years to come,"
said Robert B. Catell,  Chairman and CEO of KeySpan  Corporation.  "The enhanced
scale and  purchasing  power of National Grid and KeySpan will generate  savings
that we are sharing with LIPA."






National  Grid/KeySpan  has also  committed  to work with  LIPA to  review  Long
Island's energy requirements and help develop a long-term energy strategy.  Long
Island will also benefit from National Grid's world-class engineering experience
and expertise in addressing energy issues.

National Grid's Chief Executive,  Steve Holliday,  said: "I am delighted we have
reached  an  agreement  with  LIPA.  We are  committed  to  retaining  a  strong
front-line work force on the Island;  enhancing operational  performance through
efficiencies  of scale,  deployment  of  innovative  technology  and shared best
practices - whether they are developed in Suffolk County,  Long Island;  Suffolk
County, Boston; or Suffolk County, England."

The Management  Services  Agreement and the other related agreements are subject
to approval by the LIPA Board of  Trustees,  the  Attorney  General and New York
State Comptroller.


CONTACTS

National Grid:    Alberto Bianchetti        315 428 6932

KeySpan:          Media Relations           516 545 5052

Photographs of the announcement are available at:www.newscastonline.com/media.
                                                 ----------------------------

A short video of the announcement is available at:http://www.nationalgridus.com.
                                                  -----------------------------


About National Grid
- -------------------

National  Grid is an  international  energy  delivery  business  with  principal
activities in the regulated electricity and natural gas industries. In the U.S.,
National Grid distributes  electricity to approximately 3.4 million customers in
Massachusetts,  New  Hampshire,  New York and Rhode  Island and  natural  gas to
approximately  569,000  customers  in New York and  245,000  customers  in Rhode
Island.

The company owns the high-voltage  electricity  transmission  network in England
and Wales  and  operates  the  system  across  Great  Britain.  It also owns and
operates the high-pressure  gas transmission  system in Britain and, through its
natural gas distribution  business serves over 11 million customers in homes and
businesses in Britain. In addition,  it has a number of businesses  operating in
related  areas  such  as  LNG  importation,   land  remediation,   metering  and
interconnectors.  For  more  information,  visit  National  Grid's  web  site at
www.nationalgrid.com.


                                       2




About KeySpan
- -------------

A member of the Standard & Poor's 500 Index,  KeySpan Corporation  (NYSE:KSE) is
the largest distributor of natural gas in the Northeast United States, operating
regulated gas utilities in New York,  Massachusetts  and New Hampshire,  serving
2.6 million customers.  These customer-focused  businesses are complemented by a
portfolio of service companies which offer energy-related products, services and
solutions  to  homes  and  businesses.  KeySpan  is also  the  largest  electric
generator in New York State. The Company owns  approximately  6,650 megawatts of
generating capacity, providing power to 1.1 million customers of the Long Island
Power  Authority on Long Island and  supplying  approximately  25 percent of New
York City's capacity  needs. In addition to these assets,  KeySpan has strategic
investments in pipeline  transportation,  distribution and storage.  KeySpan has
headquarters  in Brooklyn,  New England and Long Island.  For more  information,
visit KeySpan's web site at www.keyspanenergy.com



                                       ###




                                       3