East Anglia's pig producers have been warned about the dangers of people bringing pork products onto farms as biosecurity measures are stepped up to prevent an outbreak of African swine fever (ASF).

The disease, which has been found in wild boar across the Channel in Belgium, does not affect humans but could have a potentially devastating impact on the pig industry – particularly in Norfolk and Suffolk, where about 25pc of the nation's pig herd is reared.

Defra says the most likely mode of transmission is from infected meat products being brought into pig units, and warned that catering waste, kitchen scraps or meat products must never be fed to pigs.

Norfolk farmer Rob Mutimer, of Swannington Farm to Fork near Reepham, who is also vice chairman of the National Pig Association (NPA), said: 'It was a real shock to us that it moved from Eastern Europe into Belgium.

'We are really encouraging people to look at their biosecurity, and not bringing ham sandwiches or pork products onto the farm that could get to the pigs, which is how classical swine fever came to this country before. Those of us that are old enough can remember the movement restrictions and the havoc it caused last time.

'ASF can live in frozen meat for 1,000 days, so if it gets onto farms and a lorry driver chucks a sandwich out of the window it can be a huge problem for East Anglia, where we have such a lot of outdoor pigs.'

READ MORE: East Anglian pig farmer calls for cull of wild pigs following outbreak of African swine fever in BelgiumSymptoms of ASF include fever, loss of appetite lack of energy sudden death with few signs beforehand, as well as vomiting, diarrhoea, and red or dark skin. Mortality rates can be as high as 100pc.

Anyone who you suspects the presence of the disease must report it immediately by calling the Defra Rural Services Helpline on 03000 200 301. Failure to do so is an offence.

• For more information on how to spot, prevent and report African swine fever, see the Defra website or the AHDB Pork website.