John Fetherstone, Ellesmere Port convener for trade union Unite, said: “I don’t like to see people playing politics with people’s jobs.

“We’re looking forward to seeing what GM’s next steps will be and to talking to Vauxhall in the New Year.”

Mr Fetherstone said he did not expect the sabbatical plan to be taken up by many workers.

Ellesmere Port and Neston MP Andrew Miller said Vauxhall was a stronger business than its US parent and in the Astra had a strong and successful product.

He said: “For Ellesmere Port, it’s very much time for people to keep their nerve, show faith in the strength of the business and the teamwork between trade unions and management, and hope they can weather the storm.”

Professor Garel Rhys, director of the Centre for Automotive Industry Research at Cardiff Business School, said the industry would ultimately get some form of US government backing.

He said: “This is a serious situation, but it’s not the end of the game yet.”

Professor Peter Cooke, KPMG automotive professor at the University of Buckingham, said the Government needed to think not just about car builders, but also about the thousands of companies who supply components.

His warning comes after gearbox builder Getrag Ford, which employs hundreds of staff at its Halewood plant, also sent its workers home early for Christmas, in response to falling orders.

alistairhoughton