Government scientists have identified a second outbreak of foot-and-mouth disease within the protection zone already in place. Cattle on the farm are reported to be exhibiting symptoms of the illness.

Ironically, staff at the Institute of Animal Health are now analysing the samples, on the site at the centre of suspicion as the source of the outbreak. A further 50 cattle now face a cull in an attempt to contain the outbreak.

Television news footage this evening also showed farmers in the area illegally closing footpaths, despite Government assurances the countryside would remain open.

In a further ironic twist, Merial, the company which shares a site with the Pirbright institute, will start preparing doses of vaccine as part of the Government’s contingency plan to tackle the outbreak.

Chief Veterinary Officer Debby Reynolds said: “The intensive work of Animal Health has meant that we have been able to rapidly identify this suspect case and take appropriate action swiftly. I continue to urge all animal keepers to be vigilant for signs of disease and practice strict biosecurity.”

The exact cause of the outbreak remains uncertain. A report is expected tomorrow which may pin down the source, though most experts say either the Institute of Animal Health or the American pharmaceutical company Merial are top of the list of suspects.

The Government says foot-and-mouth disease poses no risk to human health.