2,300 jobs will go if the plant closes

The French firm announced in April it was to close the plant in Ryton with the loss of 2,300 jobs. Since then workers have protested at dealerships.

Amicus and the Transport and General Workers' Union were behind the rallies.

An Amicus spokesman said they were targeting at least two dealerships in every region the union represents.

The unions, who recently began a �1m advertising campaign against the closure, said leaflets would be handed out near city centres after the demonstrations.

Between 50 and 60 people, including two MPs and councillors, demonstrated outside a dealership in Coventry on Saturday morning.

"We have had a lot of support from the public today and we are now looking at targeting the Motor Show next week," a union spokesman told BBC News.

Our campaign should serve as a warning to other companies too Derek Simpson, Amicus

Amicus general secretary Derek Simpson said: "This is a wake-up call to the company. They are jeopardising their sales and reputation by pushing ahead with closing Ryton.

"Our campaign should serve as a warning to other companies too. We will attack them in the same way if they decide to abandon their UK bases and workforces."

Tony Woodley, general secretary of the TGWU, added: "The company says it doesn't matter where cars are made, but we believe if the public knows what this company is doing, it will matter.

"These cars are being tainted by a company that talks economics but practises greed."

Owners Peugeot-Citroen has said it had looked at proposals by the unions to keep the factory open but said they were not viable.

The firm said it had consulted fully with unions and was now committed to helping workers find alternative work - giving �5m to help them do so.