Major supermarkets and restaurant chains have signed up to a voluntary labelling code to clear up confusion for consumers over where pork products have really come from, the Government announced at a conference in Birmingham.

Asda, Tesco, Sainsbury’s and Whitbread are among the retailers which have committed to the code which aims to end the confusion over labelling of pork, bacon and ham and products such as pork pies, the National Farmers' Union conference at the Hilton Birmingham Metropole was told.

Until now, the meat could be labelled as British if it was processed in this country - even if the pig had been born, reared or slaughtered abroad, where lower welfare standards could be in force.

Under the new agreement, consumers will be able to tell more easily where the meat they are buying has come from.

Companies who have signed up to the code will have to display country of origin clearly on the pack, and if they describe meat as “produced in the UK”, they will also have to put the country it originally came from.

Under the code, flags on the packaging such as the Union flag, or Welsh flag, will only be used if the pork comes from that country and the use of specific terms such as Wiltshire Cure will mean the meat used to make the product comes from the UK.

Environment Secretary Hilary Benn, who announced the code at the NFU conference, said the voluntary agreement had been reached through a task force of consumers, retailers, the Government, farmers and processors.

“I expect all major retailers to sign up and join those who have already decided to end the confusion for shoppers.

“If they don’t, their customers should ask them why they’re not in favour of clear, honest labelling,” he said.

Under the code, restaurants will make the country of origin information available to customers on menus, in leaflets or on company websites.

Marks & Spencer, Morrisons, the Co-operative, Waitrose and catering company Baxter Storey have all signed up to the code, which goes live in April.

Consumers will be able to go online to see which businesses have agreed to the voluntary agreement.

Stewart Houston, chairman of pig industry body BPEX and the National Pig Association, said clear labelling “is great news for everyone in the supply chain”, providing an easier choice for consumers, more sales of British pork for the retailer, and benefiting both the producer and the processor.

Under the details of the code, traditional British products such as Melton Mowbray pork pies, Cumberland sausage and Lincolnshire sausages will be made from UK pork unless it clearly states on the label from which other country the meat comes.

The use of imagery which suggests the food is from the UK - for example, English village scenes on packaging - will only be used if the meat is British, or they must have country of origin information on the same part of the label, while the use of terms such as “local” must be clearly defined.

And descriptions such as “free range”, “outdoor bred” and “outdoor reared” are defined in the code, which also says that imagery featuring outdoor pig farming products can only be used where the pigs have been bred or reared outside or on free range farms.