The plant specialises in manufacturing electrical equipment for the Navy and provided components for the Queen Elizabeth Class aircraft carriers, which are currently nearing completion.

Rolls Royce has decided to close Portsmouth because of a lack of future business. Staff have been informed of the decision and a period of consultation with the unions will begin shortly.

The news comes on the back of BAE Systems’ recent decision to close the shipbuilding facility in Portsmouth, with the loss of almost 1,000 jobs.

Prospect negotiator John Ferrett voiced concern that Portsmouth is once again losing high-skilled engineering jobs.

“This is yet more devastating news for workers in the area and for the local economy. Prospect members working for Rolls Royce in Cosham work in high-end design and engineering roles and have played a key part in designing and manufacturing equipment for the UK fleet.

“The decision to close the Cosham factory is a bitter blow, not least given the huge loss of jobs that is also taking place as a result of the shipbuilding closure.

“The unions will work with the company to do all we can to mitigate the job losses, but it is difficult to see how this can be achieved alongside the loss of similar jobs in the dockyard.

“There is now a compelling case for the government to intervene and give substance to its claim that Portsmouth is set to become a centre of maritime excellence. Indeed, the government’s plan to appoint a Minister for Portsmouth is meaningless if the only result is warm words and no action.”

Prospect represents a third of the staff at Rolls Royce, Cosham.