RNS Number:2122U
Marconi Corporation PLC
14 January 2004



                                                                Press enquiries:
                   Joe Kelly tel: +44 207 306 1771; email: joe.kelly@marconi.com
                 David Beck tel: +44 207 306 1490; email: david.beck@marconi.com

                                                             Investor enquiries:
          Heather Green tel: + 44 207 306 1735; email: heather.green@marconi.com

                       MARCONI SIGNS NEW SUPPORT CONTRACT
                               EXPANSION WITH BT


LONDON - January 14, 2004 - Marconi Corporation plc (London: MONI and NASDAQ:
MRCIY) today announces that it has signed a new contract with BT Wholesale to
support BT's UK national network. Designed to help reduce the operational cost
of running the network, the agreement is based on managing support and repair
transaction volumes and extends the scope and duration of an existing support
agreement. It includes support for Marconi equipment in BT's PSTN, transmission
and DSL network, as well as its core intelligent network platform.

"Reducing the cost of operating their networks is a key objective for network
operators today," said Mike Parton, Marconi chief executive. "Marconi's services
and support capability is second to none in the industry and this, together with
our knowledge of BT's network, were the key reasons we were awarded this
important contract."

Paul Reynolds, chief executive of BT Wholesale said: "This agreement is one of a
number of initiatives designed to reduce the cost base of our network in the UK.
This goes to the heart of BT Wholesale's strategy to provide our customers with
leading-edge telecommunications services, in a cost effective way."

The new enlarged agreement became effective this month.

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
NASDAQ under the ticker MRCIY.

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

Copyright (c) 2004 Marconi Corporation plc. All rights reserved. All brands or
product names are trademarks of their respective holders.

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 Corporation 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.



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