In a speech to the conference, the opposition spokesmen on agriculture and food, Nick Herbert said the campaign calls for clearer country of origin labelling on all meat products.

Mr Herbert said that an ICM poll commissioned by the Conservative party found that 51 per cent of consumers believe that food labelled as British indicates that the meat is from an animal born and bred in Britain.

"In fact, this is not necessarily the case," Mr Herbert said.

The survey also showed that 89 per cent of those questioned would support a born and bred qualification for British labelling.

The poll also found that 87 per cent felt the government should ensure country of origin labelling should be displayed on British food.

And it found that more than half would be prepared to pay a little more for food labelled and known to be British.

"The food retailers will talk about voluntary agreements until our cows don't come home," Mr Herbert said.

"The time for talking is over.

"We are publishing a Parliamentary bill to make country of origin labelling mandatory.

"I am pleased to say it is supported by your union, other industry organisations and by animal welfare organisations," he told the conference.

Mr Herbert called on the Environment Secretary, Hilary Benn to stamp out misleading labelling and to support the bill.

"I believe in markets, but markets have to work fairly," Mr Herbert said.

During his speech to the conference, Mr Benn said: "I met with the supermarkets and the Food and Drink Federation last month to see what they could do to improve country of origin and welfare labelling.

"A lot has been done, but we can do more to ensure that consumers can get the products they want and especially when they want to buy British.

"That's why I want to stamp out unclear, inaccurate or misleading labelling."