According to HalalFocus.com, some 35 scholars attended a debate on religious slaughter and all rejected the mechanisation of the procedure under halal law, according to the meeting organiser, Naved Syed, a member of Eblex’s halal steering group.

The issue is controversial, however, with some halal organisations reported to take a more pragmatic view and apparently agreeing to automated slaughter under certain conditions. It is also a delicate matter for enforcement authorities aware of the highly sensitive nature of religious slaughter.

While the meeting was happy with Food Standards Agency guidelines to local authority enforcement officers on halal food issues the scholars expressed concerns that correct practices were being ignored in many cases.

According to the guidelines slaughtermen must use a sharp knife to sever the jugular veins and carotid arteries as well as the oesophagus and trachea of animals, but not the spinal cord as this restricts convulsion, which in turn restricts the pumping out of blood.

However Syed said machine slaughter methods did result in the spinal cord being cut in 5 per cent of cases.

A survey last year showed that of 4.7 million birds slaughtered in one week using so-called halal procedures only 1.2 million used the correct manual method.

Mr Syed said: “If you are going to do halal you must do it properly.” He rejected a suggestion that following correct halal procedures was not practical on a modern, fast moving, poultry slaughterline, insisting that up to 8,000 birds an hour could be processed if four extra slaughtermen were employed."

He predicted that the rejection of automated slaughter methods by the scholars and the proper enforcement of halal manual methods would lead to legal challenges by some companies.

He added that although he organised the meeting he was not allowed to speak in the debate.

Masood Khawaji, president of the non profit authenticating body the Halal Food Authority, said mechanical slaughter methods have become necessary and some scholars and clerics are living in the past. “We have to look to the future,” he said.

Mechanised slaughter of poultry and animals under halal procedures should be permitted provided some criteria are met including ensuring that the animal is not dead before slaughter and blood is drained from the body.