Tesco has been condemned for selling live turtles which are butchered at the counter in its stores in China.
The soft shell turtles have their heads chopped off with a knife. However they remain aware and able to move their eyes for up to an hour after decapitation unless their skulls are crushed with a hammer.
Tesco also allows customers to buy live turtles in small net bags to be killed at home.
It is claimed the creatures are commonly boiled alive or have their shells removed and strips of flesh cut away while they are still alive.
Tesco insisted the butchering is carried out quickly and humanely and said it would be wrong to impose Western standards on the Chinese.
But reptile biologist Clifford Warwick said: “It is not a simple matter to decapitate these turtles because they are highly mobile, fast and elastic movers.
“As a result, often only a bit of the head will be chopped off.”
The animal welfare group Viva is calling on Tesco to abandon the trade.
Its spokesman Justin Kerswell said: “China has no animal welfare standards of any kind and Tesco are happy to take advantage of that.
“Obviously every little helps when it comes to profit.”