LONDON — A supermarket has defended selling squirrel meat as a "sustainable" form of food, amid protests by animal activists who accused him of cashing in on a "wildlife massacre".

"In a few years' time, it's going to become like rabbit," said Andrew Thornton, who introduced squirrel meat into his branch of the Budgens supermarket in north London this year.

"Squirrel is a very sustainable form of meat," he told AFP on Thursday, explaining that while it takes 15 tons of grain to produce one ton of beef, "squirrels feed from nature -- there are too many of them around."

Squirrel meat was once a common feature of the British diet and in recent years has returned, being sold by speciality game dealers and restaurants and endorsed by celebrity chefs, who have cooked up recipes for squirrel ragout and squirrel offal skewers.

It is increasingly seen as acceptable to eat grey squirrels, whose population has exploded since being introduced here in the 19th century.

Some groups now advocate culling grey squirrels to protect the domestic red squirrel, which is now a protected species.

Although he is currently out of stock, Thornton said he had been selling about 10 to 12 squirrels a week, sourced from a game supplier in Suffolk, eastern England, and "we've had a number of customers asking for it".

His actions have provoked outrage from animal rights activists, however.

"Culls of thousands of grey squirrels by so-called conservation groups to boost populations of red squirrels are irrational, inhumane and destined to fail, so it is very sad that Budgens are allowing profit to be made from wildlife massacre," said Juliet Gellatley of Viva (Vegetarians International Voice for Animals).