SC 14D1/A

                     SECURITIES AND EXCHANGE COMMISSION
                           WASHINGTON, D.C. 20549
  
                               SCHEDULE 14D-1
                              AMENDMENT NO. 11
                           TENDER OFFER STATEMENT
    PURSUANT TO SECTION 14(D)(1) OF THE SECURITIES EXCHANGE ACT OF 1934
                                    AND
                                STATEMENT ON
                                SCHEDULE 13D
                              AMENDMENT NO. 12
                 UNDER THE SECURITIES EXCHANGE ACT OF 1934

  
                             SEDGWICK GROUP PLC
                         (NAME OF SUBJECT COMPANY)
  
                      MARSH & MCLENNAN COMPANIES, INC.
                                  (BIDDER)
  
                    ORDINARY SHARES OF 10 PENCE EACH AND
             AMERICAN DEPOSITARY SHARES, EACH REPRESENTING FIVE
                      ORDINARY SHARES AND EVIDENCED BY
                        AMERICAN DEPOSITARY RECEIPTS
                       (TITLE OF CLASS OF SECURITIES)
                        815673108 (ORDINARY SHARES)
                   815673207 (AMERICAN DEPOSITARY SHARES)
                   (CUSIP NUMBER OF CLASS OF SECURITIES)
                                       
  
                            GREGORY F. VAN GUNDY
                       GENERAL COUNSEL AND SECRETARY
                        1166 AVENUE OF THE AMERICAS
                       NEW YORK, NEW YORK 10036-2774
                               (212) 345-5000
          (NAME, ADDRESS AND TELEPHONE NUMBER OF PERSON AUTHORIZED
         TO RECEIVE NOTICES AND COMMUNICATIONS ON BEHALF OF BIDDER)
  
                                 COPIES TO:
  
        DAVID J. FRIEDMAN                             MARK RAWLINSON  
       MICHAEL E. HATCHARD                              FRESHFIELDS 
 SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP             65 FLEET STREET
        919 THIRD AVENUE                          LONDON ECY 1HS, ENGLAND 
      NEW YORK, NEW YORK  10022                    (011) 44-171-936-4000 
          (212) 735-3000   

 


           Marsh & McLennan Companies, Inc., a Delaware corporation ("Marsh
 & McLennan"), hereby amends and supplements its Tender Offer Statement on
 Schedule 14D-1 ("Schedule 14D-1") filed with the Securities and Exchange
 Commission (the "Commission") on September 4, 1998 relating to the offer to
 purchase (the "Ordinary Offer") all of the (a) ordinary shares of 10 pence
 each ("Sedgwick Shares") of Sedgwick Group plc ("Sedgwick") at a price of
 225 pence in cash per Sedgwick Share and (b) American Depositary Shares of
 Sedgwick ("Sedgwick ADSs"), each representing five Sedgwick Shares and
 evidenced by American Depositary Receipts, at a price of pound
 sterling11.25 in cash per Sedgwick ADS.  This Amendment No. 11 to the
 Schedule 14D-1 also constitutes Amendment No. 12 to the Schedule 13D of
 Marsh & McLennan with respect to Sedgwick Shares and Sedgwick ADSs filed
 with the Commission on September 3, 1998.  
  
           Item 6.   Interest in Securities of the Subject Company 
  
           Items 6(a) and (b) are hereby amended and supplemented by
 incorporation by reference therein of the following information: 
  
           On November 25, 1998, Marsh & McLennan issued a press release
 (the "Press Release") which announced, among other things, that it has
 acquired or agreed to acquire 94.8% of the Sedgwick Shares (including
 Sedgwick Shares represented by Sedgwick ADSs) to which the Ordinary Offer
 relates.  A copy of the press release is filed herewith as Exhibit (a)(23)
 and is incorporated by reference herein. 
  
           Item 10.  Additional Information. 
  
           Item 10(f) is hereby amended and supplemented by incorporation by
 reference of the following information: 
  
           Marsh & McLennan also gave notice in the Press Release that it
 has issued notices to those Sedgwick shareholders who have not already
 accepted the Ordinary Offer, informing them that it intends to exercise its
 rights under Section 429 of the United Kingdom Companies Act to acquire
 compulsorily all their Sedgwick Shares (including Sedgwick Shares
 represented by Sedgwick ADSs).  In addition, the Press Release also gave
 notice that (i) the Ordinary Offer will remain open for acceptance until
 further notice, (ii) at least 14 calendar days' notice in writing will be
 given before the Ordinary Offer is closed and (iii) Marsh & McLennan
 intends to request the London Stock Exchange and the New York Stock
 Exchange to delist the Sedgwick Shares and Sedgwick ADSs as soon as
 practicable.  A copy of the notice issued to Sedgwick shareholders is filed
 herewith as Exhibit (a)(24) and is incorporated by reference herein. 

           Item 11   Material to be Filed as Exhibits. 
  
      Item 11 is hereby amended and supplemented by the addition of the
 following exhibits thereto: 
  
      (a)(23)   Text of press release of Marsh & McLennan, dated November
                25, 1998. 
  
      (a)(24)   Text of notice to Sedgwick shareholders, dated November 25,
                1998. 
  


                                 SIGNATURES 
  
      After due inquiry and to the best of my knowledge and belief, I
 certify that the information set forth in this statement is true, complete
 and correct. 
  
  
                          MARSH & McLENNAN COMPANIES, INC. 
  
  
  
                          By: /s/ Gregory F. Van Gundy 
                              ____________________________
                              Name:  Gregory F. Van Gundy 
                              Title: General Counsel and Secretary 
  
  
 Dated:  November 25, 1998 
  
  
                               EXHIBIT INDEX 
  
      (a)(23)   Text of press release of Marsh & McLennan, dated November
                25, 1998. 
  
      (a)(24)   Text of notice to Sedgwick shareholders, dated November 25,
                1998. 
  

EX-99

                                                            Exhibit (a)(23)


                                                          November 25, 1998

Not for release, publication or distribution in or into Canada, Australia
or Japan.

                      MARSH & McLENNAN COMPANIES, INC.

                          RECOMMENDED CASH OFFERS

                                    FOR

                             SEDGWICK GROUP PLC

              Commencement of compulsory acquisition procedure

Marsh & McLennan Companies, Inc. today announced that it has acquired or
agreed to acquire 94.8per cent of the Sedgwick Shares (including Sedgwick
Shares represented by Sedgwick ADSs) to which the Ordinary Offer relates.

Accordingly, Marsh & McLennan has today issued notices to those Sedgwick
Shareholders who have not already accepted the Ordinary Offer, informing
them that it intends to exercise its rights under section 429 of the United
Kingdom Companies Act to acquire compulsorily all their Sedgwick Shares
(including those represented by Sedgwick ADSs).

The Offers will remain open for acceptance until further notice. At least
14 calendar days' notice in writing will be given before the Ordinary Offer
or the Convertible Offer are closed.

Marsh & McLennan intends to request the London Stock Exchange and the New
York Stock Exchange to de-list the Sedgwick Securities as soon as
practicable.

Sedgwick Group plc is the London-based holding company of one of the
world's leading insurance, reinsurance and consulting groups. This group
provides insurance and reinsurance broking services, risk consulting,
employee benefits consulting and related financial services from more than
290 offices in 70 countries.

Marsh & McLennan Companies is a professional services firm providing risk
and insurance services, investment management and consulting. More than
50,000 employees worldwide provide analysis, advice and transactional
capabilities to clients in over 100 countries. Marsh & McLennan Companies'
stock (ticker symbol: MMC) is listed on the New York, Chicago, Pacific and
London stock exchanges. Its Web site address is www.marshmac.com.


Contact:

Marsh & McLennan              +1 212 345 5585
Barbara Perlmutter

Kekst & Company               +1 212 521 4800
Jim Fingeroth
Michael Freitag

Brunswick                     +44 171 404 5959
Alison Hogan

Sedgwick                      +44 171 377 3456
Julia Fish

J.P. Morgan, Donaldson, Lufkin & Jenrette and Cazenove, which are regulated
in the United Kingdom by the Securities and Futures Authority Limited, are
acting for Marsh & McLennan and for no one else in connection with the
Offers and will not be responsible to anyone other than Marsh & McLennan
for providing the protections afforded to their respective customers nor
for giving advice in relation to the Offers.

The Offers are not being made, directly or indirectly, in or into, Canada,
Australia or Japan. Accordingly, neither copies of this announcement nor
any related offering documents are to be mailed or otherwise distributed or
sent in or into Canada, Australia or Japan.

Terms defined in the offer document dated September 4, 1998 have the same
meaning in this announcement unless the context requires otherwise.

EX-99

                                                            Exhibit (a)(24)

      THIS DOCUMENT IS IMPORTANT AND REQUIRES YOUR IMMEDIATE ATTENTION.
When considering what action you should take, you are recommended
immediately to seek your own financial advice from your stockbroker, bank
manager, solicitor, accountant or other independent professional advisor
authorized under the Financial Services Act 1986.

      If you have sold or otherwise transferred your Sedgwick Securities
(otherwise than pursuant to the Ordinary Offer) please send this letter,
together with the accompanying documents, as soon as possible to the
purchaser or transferee, or to the stockbroker, bank, or other agent
through whom the sale or transfer was affected for onward transmission to
the purchaser or transferee. However, such documents should not be
forwarded or transmitted into Canada, Australia or Japan or any other
jurisdiction if to do so would constitute a violation of the relevant laws
in such jurisdictions. See paragraph 8 of Part B of Appendix I to the Offer
Document.

      If you have already validly accepted the Ordinary Offer in respect of
all your Sedgwick Securities you should ignore this letter and the
accompanying documents.


JPMorgan                           Donaldson, Lufkin & Jenrette

Morgan Guaranty                    Donaldson, Lufkin & Jenrette International
Trust Company                      99 Bishopsgate, London EC2M 3XD
of New York

PO Box 161
60 Victoria Embankment
London EC4Y 0JP

      To Sedgwick Shareholders who have not accepted the Ordinary Offer
made on behalf of Marsh & McLennan Companies, Inc. and, for information
only, to Sedgwick ADS holders who have not accepted the Ordinary Offer (in
both cases other than Sedgwick Securityholders in Canada, Australia or
Japan).


                                                            November 25, 1998


Dear Sedgwick Shareholder and ADS Holder

                Recommended Cash Offers for Sedgwick Group plc
                on behalf of Marsh & McLennan Companies, Inc.

      We refer to the offer document dated September 4, 1998 (the "Offer
Document") setting out the terms of the recommended cash offers on behalf
of Marsh & McLennan Companies, Inc. for all the issued and to be issued
ordinary share capital of Sedgwick and for all the outstanding Sedgwick
Convertible Bonds.

      The Offers have now been declared unconditional in all respects and
Marsh & McLennan has acquired or contracted to acquire more than 90 per
cent of the Sedgwick Shares (including Sedgwick Shares represented by
Sedgwick ADSs) to which the Ordinary Offer relates. Marsh & McLennan now
intends to acquire compulsorily all the issued and to be issued Sedgwick
Shares which it does not already own or has not contracted to acquire
(including Sedgwick Shares represented by Sedgwick ADSs) under the
provisions of the UK Companies Act 1985.

      According to the records of Computershare Services, PLC, you have not
yet accepted the Ordinary Offer in respect of some or all of the Sedgwick
Securities held by you. Accordingly, if you are a holder of Sedgwick
Shares, you will find enclosed with this letter a statutory notice
informing you that Marsh & McLennan intends to acquire compulsorily your
holding of Sedgwick Shares.

      You may still accept the Ordinary Offer (whether as a holder of
Sedgwick Shares or Sedgwick ADSs), which remains open until further notice
from Marsh & McLennan compulsorily acquires your Sedgwick Shares (including
Sedgwick Shares represented by Sedgwick ADSs)

A subsidiary of J.P. Morgan & Co. Incorporated     Regulated by The Securities
Registered as a branch in England, Branch          and Futures Authority 
No. 001366 Registered No. FC000297.  A Limited     Registered in England and 
Liability Private Company.  Registered with        Wales:2475089 
the Superintendent of Banks in the State of 
New York, U.S.A.  Incorporated with limited 
liability in the State of New York, U.S.A.  
Regulated by SFA and IMRO



To accept Marsh & McLennan's Ordinary Offer

      To accept the Ordinary Offer, if you now wish to do so and you hold
Sedgwick Shares, you should complete and return the Shareholder Form of
Acceptance (a further copy of which is enclosed) in accordance with the
instructions printed thereon and set out in the Offer Document. The
completed, signed and (if you are an individual) witnessed Shareholder Form
of Acceptance together with, if your Sedgwick Shares are not in CREST, the
share certificate(s) and/or other document(s) of title for your Sedgwick
Shares, should be returned by post or by hand to Computershare Services,
PLC, PO Box 859, The Pavilions, Bridgwater Road, Bristol BS99 1XZ or by
hand, during normal business hours only, to Computershare Services PLC, 7th
Floor, Jupiter House, Triton Court, 14 Finsbury Circus, London EC2A 1BR, as
soon as possible.

      If your Sedgwick Shares are in uncertificated form (that is, in
CREST) you should read carefully paragraph 9 of Part B of Appendix I to the
Offer Document which sets out the acceptance procedures for holders of
Sedgwick Shares in uncertificated form.

      Holders of Sedgwick ADSs may also still accept the Ordinary Offer. If
they now wish to do so, such persons should complete the Letter of
Transmittal (a further copy of which is enclosed) in accordance with the
instructions printed thereon and set out in the Offer Document and send it
by post or by hand to the US Depositary, The Bank of New York, 101 Barclay
Street, New York, New York 10286, marked for the attention of Tenders and
Exchanges, as soon as possible.

      Further copies of the Shareholder Form of Acceptance and Letter of
Transmittal are available from Computershare Services PLC and The Bank of
New York respectively at the above addresses or from Georgeson & Company,
Inc., Wall Street Plaza, New York, New York 10005, the information agent
for the Offers. Further copies of the Offer Document are available at all
three addresses.

      Any Shareholder Form of Acceptance or Letter of Transmittal received
in an envelope postmarked in Canada, Australia or Japan or otherwise
appearing to Marsh & McLennan or its agents to have been sent from Canada,
Australia or Japan may be rejected as an invalid acceptance of the Ordinary
Offer. For further information for overseas securityholders, see paragraph
16 on page 17 of the Offer Document and Paragraph 8 of Part B of Appendix I
to the Offer Document.

If you do not accept Marsh & McLennan's Ordinary Offer

      The enclosed statutory notice has the effect that, subject as stated
in the notice, Marsh & McLennan will be entitled and bound to acquire your
Sedgwick Shares (including Sedgwick Shares represented by Sedgwick ADSs) in
due course and, if you take no further action, your Sedgwick Shares
(including Sedgwick Shares represented by Sedgwick ADSs) will be so
acquired. The terms of the compulsory acquisition of Sedgwick Shares are
set out in the enclosed statutory notice.

      The consideration will only be transferred to the Sedgwick
Shareholder entitled thereto upon application to Sedgwick Group plc, c/o
Computershare Services PLC, at the address set out below at any time after
January 6, 1999 provided such application is accompanied by satisfactory
evidence of entitlement such as the relevant share certificate(s) and/or
other document(s) of title and/or an acceptable form of indemnity in
respect of the Sedgwick Shares formerly held.

      The consideration for Sedgwick Shares represented by Sedgwick ADSs
will be transferred to The Bank of New York as depositary for the Sedgwick
ADSs. The consideration will only be transferred to holders of Sedgwick
ADSs upon application to The Bank of New York at any time after January 6,
1999 provided that such application is accompanied by satisfactory evidence
of entitlement such as the relevant certificate(s) and/or other document(s)
of title and/or an acceptable form of indemnity in respect of the Sedgwick
ADSs held. Holders of ADSs will be paid the consideration for their
Sedgwick ADSs in US dollars converted from pounds sterling.

      Any query or communication connected with this letter or its
enclosures should be addressed to Computershare Services PLC, PO Box 859,
The Pavilions, Bridgwater Road, Bristol ES99 1XZ (tel 0117 941 7700) or, if
you are a holder of Sedgwick ADSs, to The Bank of New York, 101 Barclay
Street, New York, New York, 10286 (tel 1800 507 9357) or Georgeson &
Company, Inc., Wall Street Plaza, New York, 10005 (tel 1 800 223 2064).

                             Yours faithfully,

Terence C. Eccles                               Clifford S.H. Hampton
Morgan Guaranty Trust                        Donaldson, Lufkin & Jenrette
Company of New York

      J.P. Morgan, Donaldson, Lufkin & Jenrette and Cazenove, which are
regulated in the United Kingdom by The Securities and Futures Authority
Limited, are acting for Marsh & McLennan and for no one else in connection
with the Offers and will not be responsible to anyone other than Marsh &
McLennan for providing the protections afforded to their respective
customers nor for giving advice in relation to the Offers.

      The Ordinary Offer is not being made, directly or indirectly, in or
into Canada, Australia or Japan. Accordingly, neither copies of this letter
nor any related offering documents are to be mailed or otherwise
distributed or sent in or into Canada, Australia or Japan.

      The members of the Offer Committee of Marsh & McLennan listed in the
Offer Document accept responsibility for the information contained in this
letter and the enclosed notice and to the best of their knowledge and
belief (having taken all reasonable care to ensure that such is the case)
the information contained in this letter and the enclosed notice is in
accordance with the facts and does not omit anything likely to affect the
import of such information.

      Terms defined in the Offer Document have the same meanings in this
letter unless the context requires otherwise.