[LETTERHEAD OF CENTRAL BANCORP]


                                 August 1, 2001



Richard Lashley and other members of the
PL Capital - Archimedes Overseas Ltd. Group
c/o Guernsey Financial Services Commission
La Plaiderie Chambers, La Plaiderie
St. Peter Port, Guernsey
Channel Islands, GY1 1WG
and
40 Swiss Partner
23 Schanzengraben
8039 Zurich
Switzerland
and
20 East Jefferson Avenue
Suite 22
Naperville, Illinois 60540

Dear PL Capital - Archimedes Overseas Group:

     Your July 31,  2001  letter is replete  with  self-serving  inaccuracy.  Be
advised that we will not dignify with comment, and reject, each and every one of
your statements in the entirety. By way of illustration only, we remind you:

          1)   The board of directors of Central Bancorp determined  unanimously
               (that is,  including its outside  directors,  not its management)
               that your group is an Adverse  Person within the criteria  stated
               in the  Shareholder  Rights Plan subject to 10% share  ownership.
               That  determination  may be  made  at any  time  and  serves  the
               Company's stockholders' best interests;

          2)   Anyone  joining  with your group  within  the  meaning of Section
               13(d) of the  Securities  Exchange Act or Rule 13d-3  promulgated
               thereunder,   such  that  together  you  and  they   collectively
               beneficially  own 10% or more of the Company's  shares will, with
               you,  become  subject to the voting and economic  dilution of all
               such shares of Company stock. You and they need to know that.

August 1, 2001
Page 2


          3)   The board of directors  unanimously  determined that this bank is
               not for sale,  notwithstanding  your group's margin loan financed
               publicly announced short-term Schedule 13D agenda.

          4)   You feign  unhappiness  with the bank's  performance  only having
               recently  bought  your shares for the purpose of raising a cry of
               "sell the bank." If you were truly unhappy with performance,  you
               should  never have bought,  or should sell your  shares,  not the
               bank.

          5)   Your  group  chose to exceed  the  Massachusetts  5%  "interested
               stockholder"  threshold  without first obtaining  approval of the
               Company's directors. Accordingly, you will not be able, by reason
               of  Massachusetts  statute,  to effect your  announced plan for a
               merger of this Company with any entity for three years unless you
               obtain approval of such merger by 90% of shares not owned by you,
               including  shares owned  through an ESOP through which shares are
               confidentially  voted  sufficient  that when voted in  employees'
               best interest (and stockholders' best interest) would reject your
               plan outright.  Central Bancorp's employees serve its communities
               daily,  not  Naperville,  Illinois  or the Channel  Islands,  and
               thereby serve all stockholders.

     At the annual  meeting on July 26,  2001,  I told you that I would meet you
for as long as you desire, any time, any place, Naperville, Zurich, you name it.
But don't  attend an annual  meeting,  fail to speak,  and then pretend that you
were not given an opportunity to speak your mind at the meeting and also offered
a meeting with me at length, any time, anywhere.


                                          Sincerely,

                                          /s/ William P. Morrissey

                                          William P. Morrissey
                                          Senior Vice President