Officials have given the all-clear to the two Bernard Matthews poultry farms in East Anglia hit by reports of avian flu last week after determining the strain was not dangerous.

The Department of the Environment, Food & Rural Affairs confirmed yesterday that the H6N1 virus present at "two poulty farms in East Anglia" was of “low pathogenicity” – and that restrictions imposed on the two sites were to be lifted.

Last week it emerged that the virus had been detected at two sites operated by Norfolk turkey giant Bernard Matthews, although authorities quickly ruled out the presence of the highly pathogenic H5 and H7 strains.

“Further laboratory tests have now confirmed that the H6N1 avian influenza virus present at two poultry premises in East Anglia is of low pathogenicity,” Defra said in a statement.

“This means that the routine restrictions put in place while the investigations were ongoing are no longer required and have now been lifted as the presence of a statutory notifiable disease has been ruled out.”

It added: “It is important that poultry keepers remain vigilant by looking for any signs of disease in their birds. Any concerns should be reported immediately to their local vet or reported to the Animal Health Agency so that statutory notifiable disease can be ruled out promptly.”