Animal welfare groups say thousands of sheep slaughtered in France at the weekend endured unnecessary suffering.

The sheep, many of which are believed to have been exported from Britain and Ireland, were killed for the Muslim festival of Eid el-Kebir.

Andrew Burroughs: French Muslim festivals are breaking as many Islamic laws as they are European ones

The RSPCA, which has monitored slaughtering at the festival for several years, says the killings were not only cruel but also illegal.

The French Government promised last year to enforce legislation implementing the European Union's directive on slaughter, which makes the religious killing of animals outside an abattoir illegal.

But the RSPCA says its undercover inspectors found many sheep being slaughtered in the open, without being stunned first.

It is to submit evidence to the European Commission urging it to act.

Law not enforced

RSPCA Chief Superintendent Barry Fryer, said: "Many of the animals were slaughtered by inexperienced people who prolonged their suffering by using inappropriate equipment in appalling conditions.

"We have gathered evidence of roads being closed and police controlling crowds at several Eid el-Kebir festivals in and around Paris.

"Therefore the French authorities are clearly failing to enforce the legislation."

Apart from concern over the sheep being killed by inexperienced slaughterers who had not stunned them first, welfare groups oppose the long distances many of the animals would have had to travel to their final destination.

Earlier this month, the Farm Animal Welfare Minister, Elliot Morley, repeated the UK Government's preference that meat should be exported "on the hook, not on the hoof".

There is also opposition to the slaughtering of animals in plain view of each other, as happened in France.

Not distressed

But research at the department of clinical veterinary science at Bristol University suggests this may not be a serious problem.

Dr Haluk Anil, of the department, told BBC News Online: "We carried out two separate studies, one on pigs and the other on sheep.

"We looked at the animals' heart rates and other stress indicators, and we monitored their behaviour.

"Both studies showed no sign of distress in the animals when they were able to see others being slaughtered nearby."

All food animals should be stunned before killing, campaigners say

In Britain, the religious slaughter of animals outside an abattoir was banned this year for the first time.

RSPCA inspectors are investigating an incident in Stoke-on-Trent last Saturday, where carcasses were removed following reports of illegal slaughter.

Religious slaughter at an abattoir does not have to involve stunning the animals first.

Those killed under the Jewish shechita system and for Muslim halal meat may die without stunning.

But the Humane Slaughter Association, which works to improve conditions for slaughter animals, says stunning is now common in halal slaughter.