A farmer, whose flocks have suffered repeated attacks by marauding dogs for more than 20 years, has shot dead a dog seen worrying his sheep.

Robert Wallis, who has farmed the 750-acre Zouch Farm, Culham near Abingdon, since 1974, killed the black-and-white collie-Staffordshire cross as it cornered three sheep in the meadow next to Abingdon Town Football Club.

The dog was shot after it ignored repeated calls to leave the terrified animals, which had been singled out of the 100-head flock of mule lambs.

The carcass of the dog, which was not carrying any identification, was taken to the Abivale Veterinary Hospital in Abingdon where it will remain for seven days for any owner to claim it.

During the incident, several lambs leapt into the nearby River Thames to escape their barking tormentor. They were chased to the point of exhaustion. One was not expected to survive.

Mr Wallis, 53, said he had been alerted to the sheep-worrier by Abingdon police.

He said: "We found one sheep in distress and another looked dead. The dog, which was on its own, had three sheep in a hedge. We called it and tried to catch it, but it wouldn't come, so we shot it."

It is not the first time Mr Wallis has had trouble with dogs worrying his sheep.

He said: "It's an ongoing problem, particularly so where you get a farm next to a town.

Albert Honey, the Thames Valley Police animal welfare officer, said: "The damage caused to the sheep by this dog was quite distressing, and I hope that all owners of dogs, if they value them, will keep them under proper control at all times."