The MPs said the ambassador accepted the meat with enthusiasm and planned to eat it himself.

Liberal Democrat Chief Whip Paul Tyler and shadow Agriculture Minister Colin Breed delivered the joint to Daniel Louis Bernard at the French Embassy in London.

Mr Tyler said: "He accepted it with considerable enthusiasm and looked forward to it. He said ambassadors have to take risks on behalf of their country and he was delighted to live dangerously."

But he added that the ambassador "promised to relay back to the French Government in Paris the particular concerns we raised of the wider issues of trade and European relations".

The move to draw attention to the French beef ban follows last week's threat by the Prime Minister Tony Blair to take the French to court unless the ban is ended.

The two MPs also had a 30-minute meeting with the ambassador inside the embassy where they warned him that the French ban could lead to a retaliatory ban on French products.

No food is 'risk-free'

Mr Tyler said this could affect imports of products such as Chablis, Champagne, Camembert and Cognac.

He admitted that presenting Mr Bernard with the joint, donated by a butcher in his Cornish constituency, was a stunt, but he said: "The French cannot expect others to obey European rules if they are not."

He added: "No food is risk-free. If our supermarkets start saying to their French suppliers 'Sorry, we can't sell your stuff' it will be very serious indeed."

The MPs visit to the French embassy comes as hundreds of farmers are planning to converge on Poole harbour in Dorset on Tuesday night to demonstrate against the ban.