The government has admitted there are no routine checkups on fish welfare at slaughter, after an investigation found no department would take responsibility.

Campaigners have said this means fish face cruelty with no repercussions for those who fail to meet their welfare needs, and have asked that fish are given the same oversight as other farmed animals.

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.

A government spokesperson admitted that in England and Wales, there was no routine animal welfare inspection programme at farmed fish processing premises.

While they claim the Animal and Plant Health Agency (Apha) did checkups in Scotland, freedom of information requests submitted by the Humane League to the Scottish government reveal there is no established process for regular welfare inspections at fish processing sites. The Humane League did not include Northern Ireland in the scope of its investigation.

Apha confirmed that it did not have “a routine programme of official inspections at fish processing sites”.

Scotland is the third biggest producer of farmed salmon in the world. The biggest, Norway, has a law mandating the pre-slaughter stunning of farmed fish. Scotland, England and Wales do not. The most recent estimate, from 2017, was that 22-52 million farmed salmon are farmed and slaughtered in the UK each year.

The same issue applies to trout farming in England. The trout industry has its own certification scheme, Quality Trout UK (QTUK), including standards for pre-slaughter stunning, but these are not enforced by the government and there are no routine checks.

Responses to freedom of information requests show not one public body has a clear understanding of what regime is in place, with the Food Standards Agency, the Fish Health Inspectorate, local government environmental health departments and Apha all confirming they do not conduct checks on fish farms in England. This means no government officials are monitoring fish welfare at the time of killing.

Cordelia Britton, the head of campaigns at the Humane League UK, said: “It is alarming that apparently zero government officials are inspecting fish welfare at slaughter. From our correspondence it seems clear that no relevant agency knows what’s going on, with each institution passing the buck to another. Without proper oversight, cruelty goes unnoticed. It is time for the government to take responsibility for how farmed fish are slaughtered, as they do for other farmed animals.”

Campaigners are calling for farmed fish to be given similar rights to other farmed animals. In the last few years there has been debate among scientists over the extent to which fish can feel pain, which is a growing area of research. In 2018 the science writer Ferris Jabr found that “the collective evidence is now robust enough that biologists and veterinarians increasingly accept fish pain as a reality”.

Dr Vicky Bond, the managing director of the Humane League UK, said: “Fish are often forgotten in discussions and decisions on animal welfare, and this is wholly unjustified. The scientific and public consensus is that they feel pain, so refusing farmed fish the same protections afforded to land animals is completely irrational. The government animal welfare committee suggested the law be updated with detailed stunning requirements back in 1996, and 25 years later farmed fish still have the same inadequate safeguards. This needs to change.”

A Defra spokesperson said: “The UK has some of the highest animal welfare protections in the world, including when animals are slaughtered or killed. We are carefully considering issues raised in the review of the welfare of animals at the time of killing (England) regulations, including detailed protections for the welfare of farmed fish.”