Packs of wolves are roaming the French countryside, devastating livestock herds and putting farmers at loggerheads with conservationists.

The grey wolf was hunted to extinction in France in the 1930s, but since the early 1990s, packs have been crossing from Italy and have now gained a tentative foothold in the country.

They have now spread throughout the French Alps, across the busy Rhône valley into the Massif Central and up the eastern border of France to the Jura and Vosges mountains, in about 20 to 25 packs.

Some have also ventured into the agricultural French lowlands, and reached as far north as the border with Belgium.

Conservationists are delighted that the wolf is thriving in France again, with packs growing at a rate of about 20% a year.

But for those whose livelihoods depend on livestock, the return of the wolf is not so welcome. Experts believe that the number of sheep killed by wolves in the last five years has doubled, with 20,000 being hunted down.

"They're killing shepherding as I know it," Bernard Bruno, 47, a farmer from the southern Alps who has lost at least 1,000 sheep, told the New York Times.

He had scant time for environmentalists.

"You go talk about the bear, the wolf, about nature that's a bit wild, and you send them all off dreaming.

"Come ask us, the shepherds, about putting sharks in the Mediterranean," he added wryly. "You'll get 99% in favour. I don't go swimming, I don't give a damn!"

Jean-Baptiste Schreiner, a farmer in the lowlands 'little Champagne' region in the Aube and Haute-Marne, told the Independent on Sunday: "Wolves here? In the mountains, or in the forests, maybe, but this is flatter country, farming country. No one expected ever to see wolves here again. Even people in the town are scared."

Wolves are a protected species in the EU, and it is illegal to kill them in large numbers and without a special permit. But farmers are asking the government to rescind the law, and allow them to hunt the predators and protect their flocks.

The government has agreed to some of their demands, and is allowing about 24 wolves a year to be culled. Authorities have advised farmers to guard their flocks with dogs and fences.

Conservationists argue that in Spain and Italy, where growing numbers of wolves roam wild, farmers have been able to protect their livelihoods without the need for mass culls.

However, farmers say with packs expanding at their current rate in France's agricultural heartlands, these measures are ineffectual.

"They should be shot on sight," Schreiner told the paper. "We should have the right to hunt them. Maybe there is a place for them in the mountains, but you cannot allow wolves to roam in countryside like this. There is no room for them.

"They have roe deer and other game to eat in the forests but it is much easier to attack sheep enclosed in a field. Because we don't hunt them, they no longer fear humans."