Tourists are being warned about the dangers a foreign pork pie or ham sandwich could do to our pig industry as part of a new campaign to keep a devastating animal disease outside the UK's borders.

Posters will be put up at UK airports and ports this summer to highlight the risks of bringing in pork products contaminated with African swine fever (ASF) - a major threat to one of East Anglia's key farming sectors.

Although the disease poses no threat to human health it is fatal for pigs, and has already spread widely across Asia - including China and Vietnam - and parts of central and eastern Europe.

Defra says this has led to the deaths of more than 800,000 pigs and wild boar in Europe and an estimated 4m pigs in Asia, forcing global pork prices to rise.

One of the main ways the disease can be spread is by holidaymakers or travellers bringing potentially contaminated pork products - including preserved and processed meats, ham or pork sandwiches - with them from infected areas. To do so is an offence, and can result in prosecution and a large fine.

To prevent a catastrophic outbreak in the UK, border officials will enforce controls on illegal meat by searching freight, passengers and luggage and will seize and destroy illegally imported meat products.

Alastair Butler, of Blythburgh Free Range Pork, near Southwold, said the recent seizure of contaminated meats by port authorities in Northern Ireland proved how serious the risk is.

"Because of the nature of our high-welfare pigs being outdoors it would be very difficult to control that disease if it came into this country," he said. "It would spread very quickly and it would cripple our industry.

"It has to travel across water to get here, and that is why this campaign is so important. There is absolutely no reason for people to bring pork products back into this country. The risk is far too great. If you do have a sandwich on the way home then eat it on the plane or put it in the bin.

"It is done out of complete ignorance and we need to educate people about the what the risks are, I don't think the average person would consider that if they brought home a pork pie and it got eaten by a pig, then it could contract the disease. But that is what could happen."

The disease can also be spread via contaminated clothing, footwear or equipment, so pig producers have also been urged to ramp up their biosecurity measures on farms.

Dr Zoë Davies, chief executive of the National Pig Association, said: "We have always stressed that the biggest threat to our pig herd is from products coming in from affected countries, so this is an important step to help keep ASF from entering our country.

"The government has estimated that a 'reasonable worst-case scenario' ASF outbreak could cost the country £90m. We believe the figure would be much higher and that is why we need to mobilise every available resource and effort to help prevent such a catastrophe."