Marconi, which has cut half its workforce in the last two years to a current level of 8,000, is to cut another 1,000, concentrating this latest round of redundancies in Liverpool and Coventry.
Spokesman David Beck said the process is at the start of a 90 day consultation period with employees and unions. He added that the troubled telecoms group is hoping to secure the 1,000 job cuts through voluntary redundancies, although compulsory lay-offs cannot be ruled out.
Marconi, which grew out of the defence firm GEC, attempted to turn itself into a global telecom player through a costly acquisition spree during the late 1990s. But the telecoms downturn came just as the company completed its transition, leaving Marconi with massive debts.
The British company has sold off parts of the business and has been involved in lengthy negotiations with its banks to try to restructure what is left.
In July Marconi reported it had made a £152m loss in the three months to June with sales dropping a further 22 percent compared with the same period last year. Marconi which has £3bn in debt, reported in the first quarter.
Marconi shares opened unchanged on Thursday at 3.93p. The stock peaked in September 2000 at 1250p.