The strain of the disease found is identical to that used for vaccines at the Pirbright Laboratory. Environment Secretary Hilary Benn said inspectors would check the facility, and an urgent review of biosecurity there would also be carried out.

He urged people to remain vigilant as the source had not been confirmed.

And he commended the authorities for their swift reaction to the outbreak at the farm, three miles from the Pirbright facility where the Institute of Animal Health is based.

Mr Benn told BBC News 24 Sunday the link to the laboratory was a "promising lead", but he added: "We don't know for sure, and therefore it's very very important that people continue to be vigilant."

There had been reports of possible foot-and-mouth infection at four other farms, but these had all tested negative for the disease, he said.

The Department for the Environment, Food and Rural Affairs (Defra) has increased the size of the protection and surveillance zones covering farms in the area.

Source: BBC News