Workers at a Mill Hill farm are warning pet owners to be vigilant after their lambs were attacked by foxes.

Belmont Children’s Farm has had to increase the number of alpacas guarding the fields from two to five after four of their lambs were decapitated by foxes.

Farm manager at Belmont Lucy Surridge said: “Our shepherd Luke Walker found the corpses of four headless lambs in the field last Sunday and the Thursday before that. These lambs were barely two weeks old and so were an easy target for a fox.

“It was very upsetting to lose the lambs in that way, rather than due to natural causes. The foxes have also taken six ducks. We’ve had fox attacks before, but not on that scale.”

Ms Surridge added these lambs were even more precious than those lost in previous years, because they were part of a flock of 233 “London lambs”, the first lambs bred on London soil, which farm owner Andrew Reid plans to sell as “authentic” London meat.

She said: “They’re unique, they’re the first lambs to be born and raised on grass in London in our new rearing programme. They will later be sold to London caterers.”

Mr Reid thinks the foxes that attacked the lambs were urban foxes released into the land around the farm by boroughs closer to the centre of London.

Ms Surridge added: “We’re a huge open green space with 380 acres and we lead right onto Totteridge Fields Nature Reserve, we’re the first big green space people from the inner boroughs come to, so the foxes are released here.”

“I’d like to warn people in the area to keep an eye out for foxes, especially those with pet rabbits.”

She added the farm had increased the number of alpacas, which have a natural instinct for deterring foxes, that were guarding the lambs, and shepherds were checking the lambs at 11pm and 4am every night.

She said: “We have asked Barnet Council for help, there is little more we can do.”