Lambs dumped in a skip and set on fire were not infected with foot-and-mouth disease.

Firefighters discovered about a dozen lambs dumped in skips at Brown House tip, at Hill End, Frosterley, County Durham, on Tuesday night.

A fire had been started to burn the bodies. Inquiries are under way to trace the farm where the lambs originated, but Maff has confirmed the animals were disease-free.

Specialist fire crews were drafted in once firefighters realised the potential seriousness of the incident, while clothing worn by the firefighters was bagged and their vehicles hosed down with disinfectant because of the risk of spreading foot-and-mouth.

Soldiers were flown in from RAF Leeming to guard the compound until officials had finished testing the tip and the lambs were disposed of.

Bob Dobbie, regional coordinator of the Northern Disease Emergency Centre, said: "I strongly deplore anyone who would take these lambs and dispose of them in this way, both from an animal welfare perspective and also it takes away resources which should have been used to fight real cases of foot-and-mouth.

"I would like to know the kind of person who would do that."