Scientists say pain is not a straightforward concept and it can take many years of research to establish whether or not certain animals can feel it. But campaigners argue there is now mounting evidence that lobsters and crabs do suffer when plunged into boiling water.

The British Veterinary Association, along with celebrities such as the wildlife presenter Chris Packham, wants the Environment Secretary Michael Gove to grant the animals extra protection in a forthcoming Animal Welfare Bill.

There are practical reasons to boil some crustaceans alive – their meat tends to spoil particularly fast, but campaigners say there are more humane killing methods that will have little impact on the food's preparation.

In response, the government said it was committed to the very highest standards of animal welfare.