An undercover investigation by Animal Equality into a Scottish salmon slaughterhouse this year showed fish having their gills cut while conscious and being repeatedly and painfully clubbed, with it taking up to seven blows to stun the animals.

Campaigners said the fish faced “vicious and imprecise bludgeoning”, and many fell to the floor to suffocate. Unlike farmed land animals, which have legislation for them to be slaughtered as humanely as possible, the fish farming industry sets its own standards regarding humane slaughter.