Tony Woodley, joint general secretary of Unite, said he had spoken to Gordon Brown on the phone to call for action to stop the factory in Bootle, Merseyside, being closed. Mr Woodley made the plea hours before he joined more than 200 Rolls-Royce workers and their supporters in a march through Liverpool city centre.

The joint general secretary of Unite also said that he would be meeting the Prime Minister early next week to "review" the current situation.

He said: "It's not a case of 'the Government haven't helped'. We have a company at the moment that isn't listening. We've got a company that's making massive profits, we've got a plant that is very profitable, it's got good, strong order books and all we've got here is corporate greed.

"Our kids later will pay the price and that's why I have made contact with Gordon Brown this morning asking him to personally intervene now. This is a blue chip, major British manufacturing company and they rely on our Government for orders and grant aid and they have had tens of millions of pounds from this Government in the past.

"My message is this: if they can't support our country and our jobs then they are not entitled to taxpayers' money for projects in to the future. So Rolls-Royce have to change their mind and this Government has got to help change their minds.

"We are hoping to meet the Prime Minister early next week as there is no justification for the closure."

The future of the plant, which makes turbines for the aviation industry, had been in doubt since the company launched a review in November last year.

Workers have staged demonstrations against the review and collected 20,000 signatures of support in a petition which was handed to Downing Street.

Union leaders claim Rolls-Royce intends to transfer manufacturing to its plant in Mount Vernon in Ohio, United States. Holding placards with the words "Keep Rolls-Royce pride on Merseyside" and waving Union Jack flags, the demonstrators marched to the front of St George's Hall in Liverpool.