The head of the British Veterinary Association (BVA) has provoked anger from religious groups by calling for an end to traditional Jewish and Muslim methods of animal slaughter.

John Blackwell wants to ban the practise of cutting animals’ throats without stunning them first.

Jewish groups variously called his remarks “scandalous”, “a dereliction of duty” and “completely misleading”.

Clearly this is an emotive issue. What about the facts?

How do Jews and Muslims slaughter animals?

UK law currently makes it compulsory for animals to be stunned with gas, an electric shock or a metal bolt fired against the forehead. But Muslims and Jews are exempt from the regulations in deference to their strong beliefs on food preparation.

Both religious groups demand that an animal’s throat be cut quickly by hand with a very sharp knife to minimise its suffering. Each religion has many other minor rules and complexities surrounding the act of slaughter.

Cutting the major arteries means the blood supply to the animal’s brain is cut, which should render it unconscious within seconds and incapable of feeling pain.

But the extent to which the animal suffers at the moment of death and how long the ordeal lasts is hotly disputed.

The basic act of cutting the throat and letting the animal bleed to death isn’t much different to non-religious slaughter.

The main difference is that the kosher and halal traditions dislike the practice of stunning animals before they are cut, believing that the animal should be free from any injury at the moment of death.

Some Muslim scholars have said that stunning can be compliant with Islamic law, and it would appear that Muslims are in practice less strict on the point than Jews, as evidenced by this survey of slaughterhouses by the Food Standards Authority.

The 2011 research found that more than 80 per cent of cattle, poultry, sheep and goats are in fact stunned before they are slaughtered in halal abbatoirs.

By contrast, Jewish law absolutely forbids stunning animals before their throats are cut, and the practice appears to be unknown, according to the same survey.

What about stunning afterwards?

Interestingly, the Food Standards Authority survey found that 10 per cent of cows slaughtered according to the Jewish Shechita protocol were stunned after being cut.

The BVA calls post-cut stunning “a valid means of reducing the suffering of animals at slaughter” and says it “presents a highly desirable refinement if government policy does not change”.

Could this be a good compromise, and one which satisfies Jewish doctrine, since the animal is not being damaged before the moment of death?

A spokesman for Shechita UK, which campaigns for Jews to continue to be allowed to carry out religious slaughter, said rabbinical authorities do not accept post-cut stunning, as it undermines the whole argument that the traditional method is as humane as any other.

Other Jewish sources suggest that religious opinion is not quite unanimous on the point. The Conference of European Rabbis has called post-cut stunning “religiously controversial”, saying “many” rabbis reject it.

Whatever the religious debate, it would appear that a small number of animals are being stunned after the fatal cut in kosher abbatoirs.

Is religious slaughter cruel?

Both sides cite scientific evidence to prove their case. This is a good overview of the evidence base in favour of Shechita.

The BVA refers to research using EEG scans of electrical activity in the animal’s brain. A lack of brain response would appear to indicate that the animal is insensible to pain.

A former government advisory body, the Farm Animal Welfare Council (FAWC), said in 2003 that sheep can no longer feel pain after 5 to 7 seconds, but cows showed brain activity for up to 60 seconds, and it could take as long as two minutes for a calf to become insensible.

On the argument that a very sharp knife produces a painless cut, the FAWC also says “we are persuaded that such a massive injury would result in very significant pain and distress in the period before insensibility supervenes”.

FAWC recommended the UK government end the exemption for kosher and halal slaughter, but their advice was rejected by ministers.

The EU-wide DialRel study looked at the evidence from brain scans and came to a similar conclusion, saying: “It can be stated with the utmost probability that animals feel pain during the throat cut without prior stunning.”

Much of the original research used to support both sides of the argument is decades old.

Recently the Labour peer and scientist Lord Winston, while speaking in the House of Lords against a proposal to ban kosher slaughter, said EEG readings were “unsound” as a method of measuring pain.

He added: “The only way that you could detect pain would be by positron emission scanning of the brain, which clearly does not show any activity at all within two seconds once the blood supply has been cut.”

We can’t find the research referred to by Lord Winston but we will update if come across anything that fits the description.

As well as the BVA, the Federation of Veterinarians of Europe, the Humane Slaughter Association and the RSPCA say all animals should be stunned before slaughter.

What do other countries do?

Norway, Iceland, Switzerland, Sweden and Poland have all banned slaughter without stunning. Last month Denmark joined them, with agriculture minister Dan Jørgensen saying: “Animal rights come before religion.”

Israel’s deputy minister of religious services Rabbi Eli Ben Dahan reacted by saying: “European anti-Semitism is showing its true colours across Europe.”

In other countries including Estonia, Slovakia and Austria, animals that are not stunned before the cut must be stunned after.

What about labelling?

The BVA is also calling for meat to be labelled “stunned” or “non-stunned” rather than described as halal or kosher.

They point out that since most halal meat is in fact stunned, contrary to popular belief people might be avoiding it unnecessarily.

On the other hand, there is evidence that a high proportion of meat slaughtered using halal and kosher methods enters the general food chain without being labelled as such.

Jewish groups say labelling kosher meat “non-stunned” would be discriminatory, because it implies that the traditional method is less humane.