Press Release

Marconi and Laurel Networks Reaffirm OEM Agreement and Long-term Relationship

Pittsburgh, PA, May 18, 2005 - Today, Laurel and ECI reaffirm their commitment to the Marconi relationship. Marconi Corporation plc (London: MONI and NASDAQ: MRCIY) and Laurel Networks will continue to supply IP-based, multi-service edge routing technology through their existing worldwide relationship. Earlier this week, Laurel announced its pending acquisition by ECI Telecom (NASDAQ: ECIL).

The partnership has been active and successful since early 2003. The agreement includes joint sales, marketing and development activities targeted primarily at customers requiring highly reliable, scalable multiservice and broadband routing. To date, this has included multiple wins for Marconi with US Federal Government and EMEA customers. The two companies will continue to pursue opportunities in the US Federal market, enterprise customers worldwide, as well as service providers where appropriate.

"We are pleased with the agreement between Laurel and Marconi. This partnership is an extremely important part of our channel strategy and we wish to continue this fruitful relationship," said Doron Inbar, President and CEO of ECI Telecom. "ECI delivers its solutions and products both directly and through chosen channels and we are committed to further help Laurel support Marconi and its other channel partners worldwide."

Geoffrey Doy, CEO of Marconi North America said, "We value the relationship we have with Laurel. Over the last two years, we have developed close ties between our companies that have led to a significant level of business. I can confirm that we are both committed to further developing this partnership for the benefit of our customers and our companies."

About Laurel Networks
Laurel Networks delivers routing technology that helps service providers transition from the standard Internet-only service delivery model into full-fledged triple-play networks. Designed for enhanced network scalability, Laurel's ST-series™ routers allow service providers to add advanced broadband applications, like video on demand or voice over IP, without incremental cost as the subscriber base grows. Headquartered in Pittsburgh, Pennsylvania, Laurel operates sales and support facilities across the US, Europe and Asia. Its routers are deployed by some of the world's largest service providers including: Level 3 Communications, KT, Dacom, and Arsys.

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, 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) 2005 Marconi Corporation plc. All rights reserved. All brands or product names are trademarks of their respective holders.

Press inquiries:

Carol Wolicki, Laurel Networks
(412) 809-4298
cwolicki@laurelnetworks.com

Joseph Ferrara,Marconi
(724) 742-7740
joseph.ferrara@marconi.com

Investor inquiries:
Karen Keyes, Marconi
+ 44 207 306 1345
karen.keyes@marconi.com

Industry Analyst inquiries:
Colleen Rosander, Marconi
724-742-7794
colleen.rosander@marconi.com