Samples from the carcases of two slaughtered pigs being tested for swine fever have proved negative.

The pigs were slaughtered at Cheale Meats abattoir at Brentwood in Essex which was closed down as part of the investigations into the suspected disease outbreak. All restrictions have now been lifted, levy-payers’ organisation BPEX says.

The tests were carried out last week at the Animal health and Veterinary Laboratories Agency (AHVLA) at Weybridge and were on the samples from the pigs which came from a Scottish unit which had also been placed under restrictions.

This is the second swine fever alert in the past six months and emphasises the importance of continued vigilance by producers and abattoirs, BPEX said.

African swine fever, which is harmless to humans but potentially fatal to pigs, is a notifiable disease and has advanced into Lithuania and there are fears it could be carried further into the European Union by infected wild boar.

The National Pig Association (NPA) has already urged tighter security at border posts to prevent contaminated meat being carried illegally into the country.

Britain has a fast-growing pork export market with China and other non-European Union countries.

The disease, which can survive for months in raw, cured, cooked and even frozen meat, has advanced from Russia and Belarus.

The last outbreak of classical swine fever in Britain was in 2000.

There has never been a case of African swine fever in this country, but the industry is on high alert following outbreaks in mainland Europe.

Anyone in the pig sector who suspects the disease is urged to notify the duty vet in their local Animal Health and Veterinary Laboratories Agency (AHVLA) Office immediately.