Urban terrorists or welcome wildlife, Bristol's 20th century foxes will be back for the 21st century after virtually being wiped out by a plague, say scientists.

In the leafy suburbs of Stoke Bishop, Westbury-on-Trym and Downsend, 99 per cent of foxes studied by a group at Bristol University have died in the last 18 months.

"There were so many foxes living in Bristol that it was like a timebomb just waiting to go off," said Dr Phil Baker.

"Some people were pleased to see the back of them as they can be a nuisance."

But you can't keep a good fox down and Dr Baker is confident the cunning creatures will return soon.

"They have repopulated other towns and cities after being wiped out," he said.

"It may be that some have already developed an immunity to the disease -- a virulent form of mange -- or that country foxes will move into the city and once they do they will breed very quickly.

"Love them or loathe them, the people of Bristol are going to have to live with them again."

The scientists have no idea where the epedemic started but they say it could have been brought into the city by a rural fox or by an infected dog. It is caused by mites which burrow into the fox's skin and cause terrible itching.

"Imagine how you feel when you have an itch and can't stop it," said Dr Baker. "Infected foxes may have millions of mites. The stress is enormous. They quickly lose weight, get other skin infections and die."

In 18 months, the city's huge population of about 220 adult foxes and up to 800 cubs was decimated to a total of around 150 adults and pups. Ironically, most of the survivors were those who befriended their worst enemy, man.

"Some were so friendly and trusting that they were being fed by hand by animal lovers across the city. People were able to treat them with an oral insecticide in their food which killed the mites although it didn't make them immune. "But it was impossible to stop the epedemic because we couldn't treat all the foxes. Some were too shy or evasive to catch.

"We were turned down by a veterinary authority because it wasn't licensed for dogs and cats and could even be quite toxic to some.

"A few vets offered it to people who they knew were feeding foxes by hand and some of these may have lived."

These survivors will soon form new family units and restock the city with foxes, says Dr Baker, although probably not in quite the same high numbers Bristol was once famous for. But if you had foxes at the bottom of the garden before you'll have them again.

And in the future, too, as the 21st century fox returns to Bristol, he may be tougher but he'll be just as friendly.