Aerospace firm Rolls-Royce is planning is to lose nearly 400 jobs at its plant in Ansty, Coventry, before completely shutting it down in a few years, a union has claimed.
Unite has said the company is planning to cut 378 jobs at the factory in West Midlands and has blamed the government for what it calls "short-sighted" cuts to the national defence budget for the losses.
Unite has also claimed the company is proposing to shut down the plant entirely over the next few years, adding staff were informed of the plans via an internal memo.
In a letter to Geoffrey Robinson, the Labour MP for Coventry North West, Rolls-Royce said it plans to "progressively run down defence services work carried out at Ansty by a combination of natural termination of legacy programmes or re-location of ongoing work to other facilities. This is expected to take a number of years."
A Rolls-Royce spokesman said: "We are in consultation with trade unions over reductions in our defence workforce at Ansty. We hope to achieve this without compulsory redundancies.
"Ansty also conducts civil aerospace business which is not affected. In a large and complex company there is a continuing need to align resource and customer demand. Overall group employment at Rolls-Royce remains fairly constant."
Following the email from Rolls-Royce, Robinson said he was "very shocked" at the news and that there was no prior warning there would be job losses at the plant.
He added: "We've got to resist this in any way we can. It's very bad news."
Unite national officer for aerospace and shipbuilding, Ian Waddell, said: "The blame for the loss of these highly skilled jobs in the key defence sector lies with the government and its short-sighted determination to ram through massive spending cuts in the defence budget.
"Once again, Unite calls for a coherent defence industrial strategy to be drawn up as matter of urgency to safeguard jobs and a defence industry at which Britain excels. This is vital - otherwise more high-skilled jobs will be lost, perhaps forever.
"There is a very long timescale for consultation and implementation, so we hope that compulsory redundancies will be avoided. However, the underlying reason for the job losses is the government's defence spending cuts announced a couple of years ago.
"The scrapping of the Harrier fleet, for instance, has led to redundancies at the Ansty factory, which will close. Meanwhile, work from Germany will be transferred to Rolls-Royce's site at Bristol.
"Unite will be seeking an early meeting with management to discuss the implications for our members and we will taking every step to safeguard their employment now and in the future."
Rolls-Royce employs 800 people at its 200-acre site. The plant handles the refit and repair of both aeroplane and marine engines.