Farmers are being warned to be on their guard after three 12-week-old lambs were skinned in their field in the middle of the night.

The lambs, which were not due to be sold until August, were slaughtered between Friday night and Saturday morning at Manor Farm in Waterperry, near Wheatley.

The thief rounded up the animals, slit their throats and took their meat.

Owners Bryan and Susan Fonge, who also rear cattle and poultry, have warned fellow farmers in the area to be vigilant.

Mrs Fonge, 64, who discovered the lambs' remains, said: "It was quite a shock. They had just left the skin, head and innards.

"They were only 12 weeks old and they shouldn't have been killed at this stage - they're taking animals which are not ready.

"They were born in January and we don't force feed them so they take longer to grow.

"There's no doubt whatsoever that they were butchered to eat. There was nothing amateurish about this. These are skilled people and they skinned them professionally. They knew what they were doing.

"They must have rounded them up near some houses, but nobody heard anything.

"We want to warn everybody so they can keep an eye on their own sheep."

Police are carrying out forensic tests on evidence left at the scene and have appealed for information about a white four-door hatchback spotted in the village at about 3pm on Friday.

Spokesman Tim Wiseman said: "Someone slashed the lambs' throats before butchering them.

"They must have done it before as they obviously knew what they were doing.

"We urgently need information on any suspicious people or vehicles seen in the area and we would also like to hear from anyone who has been offered cheap meat."

Last year, police launched a major investigation into the suspected shooting of 100 lambs at Horton-cum-Studley during April and May. No bullets were ever found and detectives concluded that the animals had in fact been attacked by dogs.

Anyone with information should call Thames Valley Police on 08458 505505 or Crimestoppers on 0800 555111.