Preliminary tests have shown the latest outbreak of foot-and-mouth in Surrey involves the same strain as that which infected herds last month.

The situation has thrown the agricultural industry in the south west into turmoil for a second time in two months.

Questions are now being asked as how this could have happened and what went wrong.

Cattle on an Egham farm found to have the disease have been slaughtered along with some pigs. Animals on another farm nearby are also being slaughtered on suspicion of infection, Defra said.

A national animal movement ban is now in place and the European Union has banned exports.

The Prime Minister Gordon Brown said the government had acted swiftly, and the outbreak was under control.

He rejected criticisms that the government responses to this outbreak of foot-and-mouth had been too late.

Environment Secretary Hilary Benn said immunisation of livestock was being considered. "We have put arrangements in place to be able to vaccinate if we thought that was the right thing to do," he said.

"The puzzling thing is it's more than 30 days since the last confirmed outbreak. The incubation period for foot and mouth is 2 to 14 days."

Government chief vet Dr Debby Reynolds said up to 300 cattle were being culled along with a number of pigs.

But there were real fears that the disease could have spread further, possibly by deer which roam freely in the area.

Peter Kendall, president of the National Farmers' Union, said it was a "hammer-blow" to the industry.

For farmers in the south west, the news was particularly devasting as markets in the region had just re-opened after the original outbreak in the summer. The industry was getting back to normal and was now closed again.

Yesterday, as markets closed, some still had animals in pens overnight, unable to move them without a proper licence.

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