SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                    FORM 6-K


                            Report of Foreign Issuer

                      Pursuant to Rule 13a-16 or 15d-16 of
                       the Securities Exchange Act of 1934


                        For the Month of DECEMBER 19, 2002

                         Commission file number: 0-30924


                                   MARCONI PLC

             (Exact name of Registrant as specified in its Charter)


                                One Bruton Street
                                 London W1J 6AQ
                                     England
                    (Address of principal executive offices)


(Indicate by check mark whether the registrant files or will file annual
reports under cover Form 20-F or Form 40-F.)


                             Form 20-F X   Form 40-F


(Indicate by check mark whether the registrant by furnishing the information
contained in this Form is also thereby furnishing the information to the
Commission pursuant to Rule 12g3-2(b) under the Securities Exchange
Act of 1934.)


                                   Yes   No X


              CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS


In order to utilize the "Safe Harbor"  provisions  of the United States  Private
Securities  Litigation Reform Act of 1995 (the "Reform Act"),  Marconi plc ( the
"Company")  is  providing  the  following  cautionary   statement.   Except  for
historical information contained herein,  statements contained in this Report on
Form 6-K may constitute  "forward-looking  statements" within the meaning of the
Reform Act. The words "believe",  "anticipate",  "expect", "intend", "estimate",
"plan",  "assume",  "positioned",   "will",  "may",  "risk"  and  other  similar
expressions which are predictions of or indicate future events and future trends
which do not relate to historical matters identify  forward-looking  statements.
Reliance should not be placed on such statements  because they involve known and
unknown  risks,  uncertainties  and other factors which are in some cases beyond
the control of the Company,  together with its subsidiaries  (the "Group"),  and
may cause the actual results, performance or achievements of the Group to differ
materially  from  anticipated   future  results,   performance  or  achievements
expressed or implied by such forward-looking  statements (and from past results,
performance or  achievement).  Certain  factors that may cause such  differences
include  but are not  limited  to the  following:  (1) any major  disruption  in
production  at our key  facilities;  (2) changes in the  environmental,  tax and
other laws and regulations,  which, among other things,  could cause us to incur
substantial additional capital expenditures and operation and maintenance costs;
and (3) adverse  changes in the markets for our products,  including as a result
of increased  competition in the highly  competitive  international  markets for
such products. These and other risks, uncertainties and factors are discussed in
the  Company's  Registration  Statement  on Form F-1 and other  filings with the
Securities and Exchange  Commission,  including this Form 6-K.  Shareholders and
prospective  investors  are  cautioned  not to  place  undue  reliance  on these
forward-looking  statements which speak only as to the Company's  judgment as of
the date hereof.  Any such  forward-looking  statements are not intended to give
any  assurance as to future  results.  The Company  undertakes  no obligation to
publicly update or revise any of these  forward-looking  statements,  whether to
reflect new information or future events or circumstances or otherwise.



                   MARCONI AND RT GROUP AGREE CAPITAL RETURN

                          FROM ULTRAMAST JOINT VENTURE

           Agreement to return GBP45 million cash to Marconi and settle

         all outstanding litigation relating to Ultramast joint venture

London - December 19, 2002 - Marconi plc (MONI) today announced that Marconi
Corporation plc has reached agreement with RT Group plc (in members' voluntary
liquidation), and its subsidiary RT Group Telecom Services Limited, on a return
of capital from Ultramast, the joint venture set up in December 2000. Subject to
completion of the reduction of capital, the agreement provides for both
companies to waive all outstanding litigation relating to the joint venture. On
completion, RT Group will assume full control of all of Ultramast.

Upon completion of the reduction of capital, which is expected in February 2003,
Marconi should receive approximately GBP45 million in cash, of which
approximately GBP20 million was paid into court pending the outcome of a
lawsuit between the parties in August 2002. The agreement proposes that
approximately GBP8 million cash will remain in Ultramast to finance ongoing
operations following completion of the reduction of capital.

ENDS/...

About Marconi plc

Marconi plc is a global telecommunications equipment and solutions company
headquartered in London. The company's core business is the provision of
innovative and reliable optical networks, broadband routing and switching and
broadband access technologies and services. The company's aim is to help fixed
and mobile telecommunications operators worldwide reduce costs and increase
revenues.

The company's customer base includes many of the world's largest
telecommunications operators. The company is listed on the London Stock Exchange
under the symbol MONI. Additional information about Marconi can be found at
www.marconi.com.

This press release contains forward-looking statements with respect to products,
partners, customers, future growth and other matters. Please refer to the Form
20-F report and Form 6-K reports filed by Marconi plc with the United States
Securities and Exchange Commission for a discussion of risks that could cause
actual results to differ materially from such statements.



Copyright (c) 2002 Marconi plc. All rights reserved. All brands or product names
are trademarks of their respective holders.



Contacts

Joe Kelly/David Beck

Public Relations

Marconi PLC

+44 (0) 207 306 1771

joe.kelly@marconi.com


Heather Green

Investor Relations

Marconi PLC

+44 (0) 207 306 1735

heather.green@marconi.com



                                   SIGNATURES

Pursuant  to the  requirements  of the  Securities  Exchange  Act of  1934,  the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned, thereunto duly authorized.


                                       MARCONI PLC



                                       By:     ____M Skelly____

                                       Name:   M Skelly
                                       Title:  Secretary


Date: DECEMBER 19, 2002