RNS Number:5799T
Marconi Corporation PLC
23 December 2003


                                                                Press enquiries:
                     Joe Kelly, tel: 0207 306 1771; email: joe.kelly@marconi.com
                   David Beck, tel: 0207 306 1490; email: david.beck@marconi.com

                                                             Investor enquiries:
             Heather Green, tel: 0207 306 1735; email: heather.green@marconi.com

                            MARCONI CORPORATION PLC
    MARCONI ANNOUNCES NOTES REPURCHASE AND PROVIDES NOTICE OF FIFTH PARTIAL
                                 REDEMPTION OF
                  10% GUARANTEED JUNIOR SECURED NOTES DUE 2008
                             CUSIP No. : G58129AD2
                            ISIN No. : XS0166109768

   *$17.6 million (approximately #10.0 million) Junior Notes repurchased; and
   *$51.6 million (approximately #29.3 million) Junior Notes to be redeemed
    at 110%
   *Reduces principal amount of Junior Notes to $185.7 million (approximately
    #105.4 million)

London - 23 December 2003 - Marconi Corporation plc (LSE: MONI; NASDAQ: MRCIY)
announced today that it had purchased $17.6 million (approximately #10.0
million) principal amount of Marconi $487 million 10% guaranteed Junior Secured
Notes due 2008 (the Junior Notes) for a total cash outlay, excluding accrued
interest and fees, of $19.4 million (approximately #11.0 million) in open market
transactions.

The repurchases were undertaken by Marconi Corporation plc. Under the terms of
the Group's Junior Notes indenture, the repurchased Notes will be cancelled
within 90 days and may not be re-issued or resold to any third party. Marconi
may purchase additional Junior or Senior Notes in the future.

In addition, Marconi today gave notice to the owners of its Junior Notes
pursuant to Section 3.02 of the Indenture dated as of 19 May 2003 (the
Indenture) made between the Company, the guarantors named therein and JP Morgan
Chase Bank (the Trustee) that pursuant to Section 3.08 of the Indenture $51.6
million (approximately #29.3 million) aggregate principal amount of Securities
(the Redemption Securities) will be redeemed on 12 January 2004 (the Redemption
Date).

The redemption price (the Redemption Price) shall be 110.0% of the principal
amount of the Redemption Securities redeemed plus 72 days accrued interest to
the Redemption Date.

In line with the mechanism used for the previous partial redemptions of the
Junior Notes, which took effect on 31 July, 30 September, 17 October and 2
December 2003 respectively, a pool factor will be applied to every holding.
Further details of the pool factor to be applied from the Redemption Date will
be announced once the pool factor has been confirmed by the Registrar.

This mandatory partial redemption has primarily resulted from a reduction in the
amount of cash collateral held against certain bonding facilities following
agreement with one of the Group's performance bonding providers and the expiry
of certain other performance bonds and letters of credit. Marconi will disclose
the balance of cash collateral relating to performance bonds as at 31 December
2003 when it publishes its third quarter results.

The paying agent with respect to the Redemption Securities is:

The Bank of New York
One Canada Square
London E14 5AL
England
Attention: Corporate Trust Office.

Any queries in respect of payment, pool factor or related matters should be
directed to Emma Wilkes at Bank of New York on (+44) 20 7964 7662, who are the
Registrar, the Depositary and the Paying Agent.

On the Redemption Date, the Redemption Price, together with accrued interest and
any Additional Amounts (as described in the Indenture), will become due and
payable. Unless the Company defaults in making the redemption payment, the
Redemption Securities shall cease to bear interest from and after the Redemption
Date. The Redemption Securities will be cancelled following redemption by the
Company.

In aggregate, Marconi has now repurchased or redeemed $249.6 million principal
amount of Junior Note reducing the principal amount outstanding and not owned by
Marconi Corporation plc to $237.3 million (approximately #134.7 million) as at
23 December 2003. After the fifth partial redemption scheduled on 12 January
2004, the principal amount will be further reduced to $185.7 million
(approximately #105.4 million).

(Exchange rate, #1 = USD 1.7615)

ENDS/...

About Marconi Corporation plc
Marconi Corporation plc is a global telecommunications equipment, services and
solutions company. 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 customer base includes many of
the world's largest telecommunications operators.

The company is listed on the London Stock Exchange under the symbol MONI and on
the Nasdaq under the symbol MRCIY.

Additional information about Marconi Corporation can be found at
www.marconi.com.

Copyright (c) 2003 Marconi Corporation plc. All rights reserved. All brands or
product names are trademarks of their respective holders.

This document contains certain statements that are not historical facts,
including statements about Marconi's expectations and beliefs and statements
with respect to its business plan and other objectives. Such statements are
forward-looking statements. These statements typically contain words such as
"intends", "expects", "anticipates", "estimates" and words of similar import.
Undue reliance should not be placed on such statements, which are based on
Marconi's current plans, estimates, projections and assumptions. By their
nature, forward-looking statements involve risk and uncertainty because they
relate to events and depend on circumstances which may occur in the future.
There are a number of factors that could cause actual results and developments
to differ materially from those expressed or implied by such forward-looking
statements. These factors include, but are not limited to future revenues being
lower than expected; increasing competitive pressures within the industry;
general economic conditions or conditions affecting the relevant industries,
both domestically and internationally, being less favourable than expected.
Marconi has identified some important factors that may cause such differences in
the Company's Form 20-F annual report for year ended 31 March 2003 and Form 6-K
report for the quarter ended 30 June 2003 and Form 10-Q for the quarter ended 30
September 2003 filed with the US Securities and Exchange Commission. Marconi
disclaims any obligation to publicly update or revise these forward-looking
statements, whether to reflect new information or future events or circumstances
or otherwise.



                      This information is provided by RNS
            The company news service from the London Stock Exchange

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