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                     SECURITIES AND EXCHANGE COMMISSION
                           WASHINGTON, D.C. 20549

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                               SCHEDULE 14D-1
                              AMENDMENT NO. 10
                           TENDER OFFER STATEMENT
    PURSUANT TO SECTION 14(D)(1) OF THE SECURITIES EXCHANGE ACT OF 1934
                                    AND
                                STATEMENT ON
                                SCHEDULE 13D
                              AMENDMENT NO. 11
                 UNDER THE SECURITIES EXCHANGE ACT OF 1934

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                             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. 10 to the
 Schedule 14D-1 also constitutes Amendment No. 11 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: 
  
      Based upon acceptances of the Ordinary Offer and its agreement during
 the offer period to purchase 15,000,000 Sedgwick Shares, as of 3:00 p.m.
 (London time) on November 13, 1998, Marsh & McLennan owned, had rights over
 or had received valid acceptances in respect of 513,615,729 Sedgwick
 Shares, including Sedgwick Shares represented by Sedgwick ADSs,
 representing approximately 92.68% of the outstanding Sedgwick Shares. 
  
  

                                 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 13, 1998