May 16, 2006

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                            SCHEDULE 14A INFORMATION
                                 (Rule 14a-101)

                  Proxy Statement Pursuant to Section 14(a) of
            the Securities and Exchange Act of 1934 (Amendment No. )

Filed by the Registrant  [X]
Filed by a Party other than the Registrant  [ ]

Check the appropriate box:
[ ]     Preliminary Proxy Statement
[ ]     Confidential, For Use of the Commission Only (as permitted by
        Rule 14a-6(e)(2))
[ ]     Definitive Proxy Statement
[ ]     Definitive Additional Materials
[X]     Soliciting Material Pursuant to Section 240.14a-12

                              KeySpan Corporation
                              -------------------
                (Name of Registrant as Specified in Its Charter)

                                     (N/A)
                                     -----
    (Name of Person(s) Filing Proxy Statement, if Other Than the Registrant)

Payment of Filing Fee (Check the appropriate box):
[X]     No fee required.
[ ]     Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.

(1)  Title of each class of securities to which transaction applies:
     N/A______________________________________________________________
(2)  Aggregate number of securities to which transaction applies:
     N/A______________________________________________________________

(3)  Per unit price or other underlying value of transaction  computed  pursuant
     to Exchange  Act Rule 0-11 (set forth the amount on which the filing fee is
     calculated and state how it was determined):
     N/A______________________________________________________________
(4)  Proposed maximum aggregate value of transaction:
     N/A______________________________________________________________
(5)  Total fee paid:
     N/A______________________________________________________________





[ ]       Fee paid previously with preliminary materials.

[ ]       Check box if any part of the fee is offset as provided by Exchange Act
          Rule  0-11(a)(2)  and identify the filing for which the offsetting fee
          was  paid  previously.   Identify  the  previous  filing  registration
          statement number, or the Form or Schedule and date of its filing.

(1)  Amount Previously Paid:
     N/A______________________________________________________________

(2)  Form, Schedule or Registration Statement No.:
     N/A______________________________________________________________
(3)  Filing Party:
     N/A______________________________________________________________
(4)  Date Filed:
     N/A______________________________________________________________







                                       2





The following  communication  is being  distributed  to all KeySpan  Corporation
("KeySpan")  employees that have outstanding stock options pursuant to KeySpan's
Long Term Incentive Compensation Plan on or about today, :

           Important Information Regarding Your KeySpan Stock Options

With the impending  acquisition of KeySpan by National Grid, many employees have
questions  regarding  how this  transaction  will  affect  their  KeySpan  stock
options.  The  purpose  of  this  communication  is to  address  some  of  those
questions.

Q.  What  will  happen  to my  KeySpan  stock  options  once the  National  Grid
acquisition is consummated?

     A. Any  unvested  stock  options that you may hold will vest at the time of
     the transaction.  At that time, you will receive an amount in cash equal to
     the excess of the transaction  price of $42 per share and the option price,
     less  applicable  withholding  taxes,  for  all of your  unexercised  stock
     options.

Q. Can I exchange my KeySpan stock options for National Grid stock or options to
purchase National Grid stock?

     A. No. At the time of the  acquisition you will only be entitled to receive
     a cash payment for your KeySpan stock options as described above.

Q. What are the tax  consequences  with respect to the cash  distribution  of my
stock options at the time of the acquisition?

     A. You will be taxed on the difference between the transaction price of $42
     per share and the option price.  This  difference  will be reported on Form
     W-2 for employees  (active and retired  employees)  and Form  1099-Misc for
     non-employees.

     For  example,  assume you were  granted 300 stock  options with an exercise
     price of $32 per share.  On the day before the  acquisition was consummated
     only  100  stock  options  were  vested.   Upon  the  consummation  of  the
     transaction,  the other 200 stock options will  automatically  vest and all
     300 stock  options will be exercised  for cash.  Your taxable  compensation
     will be $3,000 shown as follows:
- --------------------------------------------------------------------------------
All Options Held x Strike/Option Price = Option Cost (300 x $32 = $9,600)

All Options Held x Transaction Price = Transaction Amount (300 x $42 = $12,600)

Transaction Amount - Option Cost = Total Taxable Income ($12,600 - $9,600 =
 $3,000)
- --------------------------------------------------------------------------------
     Please note that federal,  social security,  medicare,  state, and city tax
     will be withheld where applicable.


                                       3




Q. Can I exercise my stock options prior to the acquisition?
  (Corporate Non-Insiders)

     A. Generally, you may exercise your vested stock options at any time if you
     are not a  designated  corporate  insider  pursuant  to the  KeySpan  Stock
     Trading  Policy,  so long as you do not  possess any  material,  non-public
     information regarding the Company.

  (Corporate Insiders)

     A. If you have been  designated  as an insider  pursuant  to the  Company's
     Stock Trading  Policy,  you are  prohibited  from engaging in  transactions
     involving  KeySpan  stock  other  than  during  prescribed  trading  window
     periods.  Generally,  window periods commence after the filing of quarterly
     or annual  reports  with the  Securities  and Exchange  Commission.  Please
     contact the Office of General  Counsel  (718)  403-6121,  if you are unsure
     whether you have been designated as an insider.

     Prior to the  acquisition you may exercise your vested stock options in the
     following three ways: 1) on-line at  www.options.equiserve.com,  2) through
     the  Computershare IVR system by calling  1-800-666-7401,  or 3) by filling
     out a stock option  exercise form and faxing it to  Computershare  at (201)
     222-4737.  Please note limit  orders can only be placed via the internet or
     by faxing your completed option form to Computershare. If you are a KeySpan
     officer,  the  preceding  instructions  do not apply.  You must contact the
     Office of General Counsel for option exercises during an applicable trading
     window period.

     The  following  are three  methods to exercise  your stock options prior to
     acquisition and each method has different tax implications.  Please consult
     with your tax advisors.

     Cash  Exercise - You notify  Computershare  that you want to exercise  your
     stock options and you remit payment to Computershare.  After  Computershare
     processes  your option  exercise,  you will be  notified of any  applicable
     taxes and  transaction  fees that you must remit.  When the  transaction is
     completed,  share  certificates  will  be  sent  to you or if you  request,
     Computershare will deposit shares in your dividend  reinvestment account or
     brokerage account.  Any shares retained will receive a cash distribution of
     $42 per share upon the consummation of the acquisition.

     Cashless Exercise - You notify Computershare that you want to exercise your
     stock  options  through a Cashless  Exercise  where you are not required to
     remit a payment. Computershare will purchase shares at the option price and
     simultaneously  sell the shares at the  market  price.  You will  receive a
     payment in the form of a check equal to the excess of the market  price and
     the option price, less applicable withholding taxes and transaction fees.


                                       4



     Cashless  Partial  Exercise/Sell  Enough  to Cover  Purchase  - You  notify
     Computershare to purchase shares at the exercise price.  Computershare will
     execute  the  purchase  and  simultaneously  sell some shares at the market
     price to cover the purchases of your shares,  taxes and  transaction  fees.
     When the transaction is completed,  share  certificates will be sent to you
     or if you  request,  Computershare  will  deposit  shares in your  dividend
     reinvestment  account or brokerage account.  Any remaining proceeds will be
     remitted to you. Any shares  retained will receive a cash  distribution  of
     $42 per share upon the consummation of the acquisition.

Reminder:
- ---------
Please be assured that  KeySpan is  committed to keeping you informed  about any
changes  regarding your stock options and will continue to communicate  with you
as KeySpan and National Grid work towards the consummation of the transaction.

If you have  questions  about  exercising  your stock  options,  please  contact
Computershare at (800) 666-7401.  If you have other questions  regarding how the
National  Grid  acquisition  of KeySpan will affect your stock  options,  please
contact  KeySpan's  Stock  Plans  Hotline at (718)  403-3131 or e-mail the Stock
Plans Group at financial@keyspanenergy.com.

Please  look for  additional  communications  regarding  how the  National  Grid
transaction will affect your holdings in other KeySpan  sponsored plans, such as
the KeySpan 401(k) Plan and Employee Discount Stock Purchase Plan.

Additional Information and Where to Find It
- -------------------------------------------

KeySpan  intends to file with the Securities and Exchange  Commission  ("SEC") a
definitive  proxy statement and other relevant  documents in connection with the
proposed  acquisition of KeySpan by National Grid. We filed a preliminary  proxy
statement  with the SEC on April 28, 2006.  Investors  and  security  holders of
KeySpan are advised to read the proxy  statement  and other  relevant  documents
when they become available, as they will contain important information about the
transaction.  Investors and security holders may obtain a free copy of the proxy
statement  and other  documents  filed by KeySpan with the SEC, when they become
available, at the SEC's web site at http://www.sec.gov.

KeySpan  and  its  directors,  executive  officers  and  other  members  of  its
management and employees may be deemed to be participants in the solicitation of
proxies from its security  holders in connection with the proposed  acquisition.
Information   concerning  the  interests  of  KeySpan's   participants   in  the
solicitation  is set forth in KeySpan's  Annual  Report on Form 10-K (filed with
the SEC on  February  28,  2006),  Quarterly  Report on Form 10-Q for the period
ended March 31, 2006, KeySpan's  preliminary proxy statement (filed with the SEC
on April  28,  2006)  and will be set forth in the  definitive  proxy  statement
relating to the acquisition when it becomes available.



                                       5



The following  communication  is being  distributed to all KeySpan officers that
have  outstanding  stock  options  pursuant  to  KeySpan's  Long Term  Incentive
Compensation Plan:


           Important Information Regarding Your KeySpan Stock Options

With the impending  acquisition of KeySpan by National Grid, many employees have
questions  regarding  how this  transaction  will  affect  their  KeySpan  stock
options.  The  purpose  of  this  communication  is to  address  some  of  those
questions.

Q.  What  will  happen  to my  KeySpan  stock  options  once the  National  Grid
acquisition is consummated?

     A. Any  unvested  stock  options that you may hold will vest at the time of
     the transaction.  At that time, you will receive an amount in cash equal to
     the excess of the transaction  price of $42 per share and the option price,
     less  applicable  withholding  taxes,  for  all of your  unexercised  stock
     options.

Q. Can I exchange my KeySpan stock options for National Grid stock or options to
purchase National Grid stock?

     A. No. At the time of the  acquisition you will only be entitled to receive
     a cash payment for your KeySpan stock options as described above.

Q. What are the tax  consequences  with respect to the cash  distribution  of my
stock  options  at the  time of the  acquisition?

     A. You will be taxed on the difference between the transaction price of $42
     per share and the option price.  This  difference  will be reported on Form
     W-2 for employees  (active and retired  employees)  and Form  1099-Misc for
     non-employees.

     For  example,  assume you were  granted 300 stock  options with an exercise
     price of $32 per share.  On the day before the  acquisition was consummated
     only  100  stock  options  were  vested.   Upon  the  consummation  of  the
     transaction,  the other 200 stock options will  automatically  vest and all
     300 stock  options will be exercised  for cash.  Your taxable  compensation
     will be $3,000 shown as follows:

- --------------------------------------------------------------------------------
All Options Held x Strike/Option Price = Option Cost (300 x $32 = $9,600)

All Options Held x Transaction Price = Transaction Amount (300 x $42 = $12,600)

Transaction Amount - Option Cost = Total Taxable Income ($12,600 - $9,600 =
 $3,000)
- --------------------------------------------------------------------------------
     Please note that federal,  social security,  medicare,  state, and city tax
     will be withheld where applicable.


                                       6




Q. Can I exercise my stock options prior to the acquisition?

     (Corporate Insiders)
     A. If you have been  designated  as an insider  pursuant  to the  Company's
     Stock Trading  Policy,  you are  prohibited  from engaging in  transactions
     involving  KeySpan  stock  other  than  during  prescribed  trading  window
     periods.  Generally,  window periods commence after the filing of quarterly
     or annual  reports  with the  Securities  and Exchange  Commission.  Please
     contact the Office of General  Counsel  (718)  403-6121,  if you are unsure
     whether you have been designated as an insider.

In addition to the Stock Trading Policy restrictions, all officers are requested
to pre-clear any option exercises during an applicable  trading window period by
completing an "Officer Intent to Trade Securities Form",  indicating the details
of their planned stock option  exercise.  Such form should also be completed for
any transaction in KeySpan securities.  The form is available from the Office of
General  Counsel  and will  generally  be sent to the  officers  along  with the
notification regarding the opening of a trading window period.

     The  following  are three  methods to exercise  your stock options prior to
     acquisition and each method has different tax implications.  Please consult
     with your tax advisors.

     Cash Exercise - You must notify the Office of General Counsel that you want
     to exercise  your stock  options and  complete an "Officer  Intent to Trade
     Securities  Form",  indicating  the details of your  planned  stock  option
     exercise and remit payment to Computershare.  After Computershare processes
     your option  exercise,  you will be notified  of any  applicable  taxes and
     transaction  fees that you must remit.  When the  transaction is completed,
     share  certificates  will be sent to you or if you  request,  Computershare
     will  deposit  shares in your  dividend  reinvestment  account or brokerage
     account.  Any shares  retained will receive a cash  distribution of $42 per
     share upon the consummation of the acquisition.

     Cashless  Exercise - You must notify the Office of General Counsel that you
     want to  exercise  your stock  options and  complete an "Officer  Intent to
     Trade Securities Form", indicating the details of your planned stock option
     exercise where you are not required to remit a payment.  Computershare will
     purchase shares at the option price and  simultaneously  sell the shares at
     the market  price.  You will receive a payment in the form of a check equal
     to the excess of the market  price and the option  price,  less  applicable
     withholding taxes and transaction fees.

     Cashless Partial  Exercise/Sell  Enough to Cover Purchase - You must notify
     the Office of General  Counsel that you want to exercise your stock options
     and complete an "Officer Intent to Trade Securities  Form",  indicating the
     details of your planned stock option exercise.  Computershare  will execute
     the  purchase  and  simultaneously  sell some shares at the market price to
     cover the purchases of your shares,  taxes and  transaction  fees. When the


                                       7



     transaction is completed,  share certificates will be sent to you or if you
     request,  Computershare  will deposit shares in your dividend  reinvestment
     account or brokerage  account.  Any remaining  proceeds will be remitted to
     you. Any shares retained will receive a cash  distribution of $42 per share
     upon the consummation of the acquisition.

Reminder:
- ---------
Please be assured that  KeySpan is  committed to keeping you informed  about any
changes  regarding your stock options and will continue to communicate  with you
as KeySpan and National Grid work towards the consummation of the transaction.

If you have  questions  about  exercising  your stock  options,  please  contact
Colleen Meade at (718) 403-6121.  If you have other questions  regarding how the
National  Grid  acquisition  of KeySpan will affect your stock  options,  please
contact  KeySpan's  Stock  Plans  Hotline at (718)  403-3131 or e-mail the Stock
Plans Group at financial@keyspanenergy.com.

Please  look for  additional  communications  regarding  how the  National  Grid
transaction will affect your holdings in other KeySpan  sponsored plans, such as
the KeySpan 401(k) Plan and Employee Discount Stock Purchase Plan.

Additional Information and Where to Find It
- -------------------------------------------

KeySpan  intends to file with the Securities and Exchange  Commission  ("SEC") a
definitive  proxy statement and other relevant  documents in connection with the
proposed  acquisition of KeySpan by National Grid. We filed a preliminary  proxy
statement  with the SEC on April 28, 2006.  Investors  and  security  holders of
KeySpan are advised to read the proxy  statement  and other  relevant  documents
when they become available, as they will contain important information about the
transaction.  Investors and security holders may obtain a free copy of the proxy
statement  and other  documents  filed by KeySpan with the SEC, when they become
available, at the SEC's web site at http://www.sec.gov.

KeySpan  and  its  directors,  executive  officers  and  other  members  of  its
management and employees may be deemed to be participants in the solicitation of
proxies from its security  holders in connection with the proposed  acquisition.
Information   concerning  the  interests  of  KeySpan's   participants   in  the
solicitation  is set forth in KeySpan's  Annual  Report on Form 10-K (filed with
the SEC on  February  28,  2006),  Quarterly  Report on Form 10-Q for the period
ended March 31, 2006, KeySpan's  preliminary proxy statement (filed with the SEC
on April  28,  2006)  and will be set forth in the  definitive  proxy  statement
relating to the acquisition when it becomes available.




                                       8





Additional Information and Where to Find It
- -------------------------------------------

KeySpan intends to file with the Securities and Exchange  Commission (the "SEC")
a definitive proxy statement and other relevant documents in connection with the
proposed  acquisition of KeySpan by National Grid. We filed a preliminary  proxy
statement  with the SEC on April 28, 2006.  Investors  and  security  holders of
KeySpan are advised to read the proxy  statementd and other  relevant  documents
when they become available, as they will contain important information about the
transaction.  Investors and security holders may obtain a free copy of the proxy
statement  and other  documents  filed by KeySpan with the SEC, when they become
available, at the SEC's web site at http:/www.sec.gov.

KeySpan  and  its  directors,  executive  officers  and  other  members  of  its
management and employees may be deemed to be participants in the solicitation of
proxies from its security  holders in connection with the proposed  acquisition.
Information   concerning  the  interests  of  KeySpan's   participants   in  the
solicitation  is set forth in KeySpan's  Annual  Report on Form 10-K (filed with
the SEC on  February  28,  2006),  Quarterly  Report on Form 10-Q for the period
ended March 31, 2006, KeySpan's  preliminary proxy statement (filed with the SEC
on April  28,  2006)  and will be set forth in the  definitive  proxy  statement
relating to the acquisition when it becomes available.




                                       9