They are the stuff of rural legend – but for decades, alleged sightings of big cats stalking the British countryside have been dismissed as hoax or fantasy.

Yet now the head of a Government agency responsible for investigating such incidents has declared that he believes these mysterious creatures do indeed exist.

His comments follow the release of a dossier by Natural England which lists more than 100 sightings of exotic, non-native and unidentified animals in England since 2005.

Of these, 38 were "big cats". In some cases, members of the public claimed to have seen the creature itself; on other occasions, they reported finding farm or wild animals which had been attacked or killed.

The documents – Britain's "big cats X Files" – show the extent to which Natural England takes the reports seriously.

The agency has launched several investigations, involving site visits by officials and the drafting in of specialist vets to examine injuries.

Big cat sightings have been reported all over England. In some areas they have spawned legends, such as the so-called Beast of Bodmin in the south west.

The investigations have yet to find conclusive proof of the presence of the mysterious creatures but, asked about their existence, Charlie Wilson, who coordinates reports for the Government agency, said: "The evidence is there that there are the odd, escaped, released dumped animals occurring in the wild every now and then.

"We know that. I am quite prepared to believe that. I don't think there are any breeding populations, however.

"If they are there, the numbers are so small that any risk of people encountering them is pretty small and any risks they present are somewhere approaching zero."

He added: "All reports are logged in our system. If there is only a sighting, then there is not usually much more than can be done to follow it up.

"But we are able to do so if there is something a bit more tangible that we could look at, like the carcases of other animals, or tracks. There are reports that turn out to be plausible."

One theory is that several large species, such as panthers, leopards and lynx, were deliberately released into the wild by their owners in the 1970s after the introduction of the Dangerous Wild Animals Act, which placed restrictions on the keeping of certain species.

In one "big cat" investigation, a carcase from an ostrich farm in Cambridgeshire was examined and the site was monitored.

In another, in Surrey, a roe deer was dragged over two fences, had its carcase eviscerated and was left with puncture marks. Natural England was informed by police and its officials studied photographs.

In Lincolnshire, a farmer found several of his sheep killed and eaten. On some of the carcases only the skull and spine were left. The farmer said the attack was down to a big cat and officials visited the site. Photos of the carcases were taken.

In another case, an injured horse was found in a field in Warwickshire, with claw marks scratched in it. In a further report, officials studied photographs of dead foxes, believed to have been scavenged by a big cat in Suffolk.

One big cat, spotted by a roadside between the villages of Mark and Burtle, in Somerset, was said to be as tall as a car. In another sighting in the same county, a motorist on the M5 reported seeing a big cat in an adjacent field.

While many of the investigations have been "inconclusive", others have been resolved. A supposed big cat seen in Norfolk, for instance, turned out to be a badger.

Danny Bamping, from the British Big Cats Society, said the real number of sightings would be even higher.

"Believing in big cats is not like believing in the Loch Ness monster," he said. "There is absolutely no doubt that they are out there.

"The most credible reports are from farmers, and those guys know their stuff. We have also had policemen reporting sightings to us. For every report, there are going to be others who don't bother to report it."

As well as the big cats, the Natural England dossier details other investigations which, in some cases, have found evidence of the presence of exotic species at large.

For instance, raccoon dogs – native to Asia and Russia – were confirmed as living in Oxfordshire and West Berkshire, while Siberian chipmunks, which can carry fatal diseases, have also been confirmed in Berkshire, Wiltshire and Cheshire.

Dead raccoons have been found in Kent and Hampshire, while there has also been a credible – though inconclusive – report of a living one in Surrey.

A snapping turtle, two feet long and 10 to 12 inches wide, was also discovered in Kent. The dossier states that the species "can be dangerous" and says that the animal needed trapping and destroying.

Fourteen coypus were also reported. The large South American rodent was brought to the UK by fur farmers in the 1930s, but some escaped and established wild populations.

These were thought to have been eradicated following a large-scale trapping exercise.

The new sightings could suggest that some remain at large, although none were proved conclusively.

A sighting of a wallaroo – an Australian animal which is smaller than a kangaroo but larger than a wallaby – living in Cornwall was taken as being credible, although not proven.

Other unconfirmed sightings include more raccoons and raccoon dogs, a wolf in Surrey, and a prairie dog in Buckinghamshire.

Twenty-eight of the sightings involved wild boar, which have escaped from farms and become established in some parts of the country in recent years. Sightings in other areas are still closely monitored.


/Telegraph.co.uk/