The foot-and-mouth outbreak spread to a new area of Britain today, government officials confirmed just hours before the mass incineration of animal carcasses was due to begin.
The latest outbreak, at Burdon Farm in Highampton, in Devon, was the seventh to be confirmed in what British farming leaders called a "nightmare scenario".
Confirmed outbreaks of the disease were previously confined to two clusters in Northumberland and Essex.
More than 2,000 pigs, sheep and cattle have been culled in Britain as the disease tightens its grip on the farming industry and another 2,000 animals were facing a cull at Burdon Farm.
The sheep and cattle farm is part of a chain of 13 in Devon and Cornwall owned by a sheep dealer who exports animals to Europe. Tonight the farms were under restrictions and being inspected.
Vehicles from the farm have travelled widely throughout Britain, particularly in Cumbria, British Ministry of Agriculture, Food and Fisheries (MAFF) officials said.
The disease was only confirmed among the farm's 600-strong cattle herd and vets were examining the 1,500 sheep for signs of infection.
The Devon outbreak came as a blow to hopes that the disease had been contained by slaughtering and a seven-day ban on livestock movement.
Britain's agriculture minister Mr Nick Brown said MAFF officials were trying to establish whether there was a link between the Highampton outbreak and the six Northumberland and Essex sites where the disease has been confirmed.
"This is a serious development, there's no denying that," he said.
"There could be other cases out there, we don't know. It will be discovered over the next few days."
Meanwhile, final preparations were under way for a "funeral pyre" tonight for 800 pigs on the farm thought to be the earliest site of the foot-and-mouth outbreak.
PA