The resurfacing of the viral disease has even led a scientist to say that the system being used to control the spread of the viral disease is being sabotaged from within.
Debby Reynolds, the department's Chief Veterinary Officer, was quoted by The Times as saying: "This is a developing disease situation and we have moved swiftly to put in place a temporary control zone while we investigate. At this stage disease has not been confirmed, laboratory results will follow."
The precautionary measure comes after an inconclusive assessment of clinical symptoms by Animal Health veterinary staff. The national movement ban remains in place.
Scientist Andrew King said yesterday that sabotage was fast becoming the only explanation.
King, brought in by the Institute of Animal Health (IAH), in Pirbright, Surrey, suggested that it was time to call the police.
Dr King, a former head of molecular biology at the IAH, said that bio-security was so tight that he felt the outbreak had to have been caused deliberately.
"As far as I am concerned the authorities have failed to find any chink in the armoury of the establishment's bio-security. What you are left with is human movement, which is not a matter for the institute; it's a police matter. It's very, very unlikely that it could be spread by accident. People do not spread the disease easily."
Health and Safety Executive (HSE) staff, investigating how the virus infected at least two farms three miles from the Surrey complex, concluded in their preliminary report that human movements, either deliberate or accidental, were the most likely means by which the FMD virus escaped from laboratories with strict bio-security measures designed to prevent leaks.
The IAH and Merial, the American company that shares the same site at Pirbright, were named as the two most probable sources of FMD, but investigators have so far been unable to find any evidence that bio-security procedures and equipment were faulty.
Dr King said he thought it likely that Merial would also be given a clean bill of health. "That establishment is inspected by DEFRA every six months. DEFRA grants the licence. DEFRA says it's OK," he said.
He described a range of bio-security measures to protect against leaks, including staff in contact with viruses having to shower and change all clothes.
Dr King added that the longest period after which the virus had ever been recovered from the human body after heavy exposure was 48 hours, and that involved a full body search.
Concerns that the FMD outbreak was caused by live virus escaping into the environment via the Pirbright research facility's drainage system were effectively ruled out last night.
Meanwhile, animal health workers are awaiting the results on tests of animals at a third farm in Normandy suspected of having FMD.
A total of 576 animals had been culled so far, 362 of them from the third farm linked to the outbreak, to stop the spread of the disease.