Holding(s) in Company

RNS Number:0720U
Marconi Corporation PLC
9 January 2004


The company has received the following notification today:

                    Goldman Sachs International
                    Peterborough Court
                    133 Fleet Street
                    London EC4A 2BB

The Company Secretary
Marconi Corp Plc
4th Floor, Regents Place
338 Euston Road
London
NW1 3BT

Fax No: 020 7493 1974


                                                                  9 January 2004


Dear Sir/Madam,

UK COMPANIES ACT 1985 - SECTIONS 198-203 - MARCONI CORP PLC (The "Company")

This notification relates to issued ordinary shares in the capital of the
Company ("shares") and is given in fulfilment of the obligations imposed by
sections 198 to 203 of the Companies Act 1985 (the "Act").

It has come to our attention that at close of business on 7 January 2004, The
Goldman Sachs Group, Inc., of 85 Broad Street, New York, NY 10004, USA, was
interested in 10,628,084 shares.

Of these 10,628,085 shares

a)             The interest in 4,122,058 shares arose from the interest held by
Goldman, Sachs & Co. ("GS&Co"), acting as custodian.  These shares are, or will
be, registered in the name of Goldman Sachs Securities (Nominees), Limited ("
GSSN").

b)             The interest in 4 shares arose from the interest held by GS&Co.
acting as discretionary manager, these shares are, or will be, registered in the
name of GSSN.

c)             The interest in 8,662 shares arose from the interest held by GS&
Co., acting as custodian of 4,331 American Depositary Receipts ("ADRs").  These
ADRs are, or will be, held at the Depositary Trust Company of New York.

d)             The interest in 6,497,361 shares arose from a beneficial interest
held by Goldman Sachs International.  These shares are, or will be, registered
at CREST in account CREPTEMP.

A copy of this fax is being sent to you by post.  Please do not hesitate to
contact me should you have any questions.

Yours faithfully

for and on behalf of
The Goldman Sachs Group, Inc.



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