French unions have joined the fight to save the Peugeot factory at Ryton as workers' leaders in Britain blamed the "cheapness" of UK labour for sealing the plant's fate.
Industrial action had not been ruled out by furious activists last night, who blamed Britain's labour laws for the decision to axe 2,300 jobs at the plant near Coventry.
Amicus said it was a "travesty" that British jobs were held so "cheaply" by politicians, adding that in France elected representatives would be shamed out of office if they did not fight to prevent big job cuts.
The French have a longer notice period of redundancy, workers can appoint an accountant and challenge a decision in court, and it costs £100,000 to make a French worker redundant compared to just £5,000 for a worker with 20 years' service in Britain, according to the union.
Des Quinn of the TGWU said job cuts on the same scale could never happen across the Channel because of "stronger" employment laws.
Roger Maddison, senior officer of Amicus, said: "British legislation makes it easier and cheaper to sack people in the UK.
"We were supposed to have consultation, but have been told it was a fait accompli.
"Peugeot bought Chrysler UK in 1981 for £1. If they are serious about getting out of this country it will cost them a lot more than that. Peugeot is a rich company that will have to dig deep. First and fore-most we want to keep Ryton going for the people who are here and for future generations of people in Coventry.
"But until the Government does something about our labour laws, we will continue to lose jobs in manufacturing."
The unions have also received support from the CGT, the French equivalent of the TUC, in the battle to save the plant which is due to close next year.
The CGT described the decision of PSA Peugeot Citroen to end production at Ryton in favour of a new plant in Slovakia as "scandalous".
In a letter to the union leaders in Coventry, it said: "The CGT assures the employees of Ryton and their trade union organisations of its support in the actions they will engage in to defend their employment and the life of their families."
James O'Boyle, works convener for the Transport & General union, said: "We are in jeopardy now, but other plants around France could be next."
Mr O'Boyle claimed no decision had yet been taken on what support would be sought, but he did not rule out industrial action.
"This is the start of our campaign to save jobs," he explained. "The French workers are prepared to fall square behind whatever decision we take to try to get the company to reverse that decision.
"They are prepared to take action. What form that takes is a matter for them. The French have ways of doing things we wouldn't do in this country.
"I think it's pretty clear what the inference is, in fact it's more than that. It's a commitment."
But Trade and Industry Secretary Alan Johnson, who met union leaders in Coventry yesterday, dismissed the claims.
"The argument that it is easier to sack people and get rid of them here is not true. It is not quicker to get rid of people in this country.
"It is getting the balance right between protecting workers and creating a situation where it is so difficult to shed jobs that companies don't recruit in the first place."
Meanwhile the Prime Minister insisted the British motor manufacturing industry was still going strong despite the closures of Longbridge and Ryton.
Mr Blair told the Commons: "It is inevitable that from time to time there will be these losses."
He was responding to questioning by Conservative leader David Cameron, who called the closure a "desperate blow".