NO ONE has ever solved the mystery of whether big cats really exist. The Big Cats in Britain Group stages its conference next month where experts from all over England will gather to discuss the issue.

There are many people convinced that the animals are descended from exotic pets set free in the wake of the Dangerous Wild animals Act of 1976.

Others believe that the creatures are an undiscovered species which has co-existed with humans since time immemorial.

It has also been suggested that the creatures could be descended from wild animals brought over by the Romans for games. And more wacky theories still purport that the animals are in fact visitors from another dimension similar to ghosts or "daemons" in The Golden Compass starring Nicole Kidman.

Defra has previously told BBC Wildlife Magazine that based on the evidence it does not believe there are big cats living in the wild.

Merrily Harpur (correct) who has penned a book Mystery Big Cats' is among the experts appearing at the Big Cat Conference at Tropiquaria near Watchet, Somerset over the weekend of March 7.

She is among those who believe that big cats may be daemons.

Merrily said: "Dorset is a hot spot. You have black panther-like animals and the odd puma-like animal.

"I've spent a whole book analysing what they could possibly be."

Merrily discounts the widespread explanation that the animals belonged to collectors who let them go or that they are hybrids crossed with domestic cats. She said: "It would be completely unfeasible for a big cat to cross with a domestic one. It would be more likely to be a snack. One theory is they are a species of big cat that has gone undetected.

"They are seen all over Dorset including Bournemouth suburbs, around Dorchester and big numbers seen in Bridport. Sightings seem to be growing. It could be people are more ready to come forward. People used to be afraid they'd be laughed at. Now they're not."

At the Watchet conference Merrily will discuss and assess the evidence and parallels with the mysterious black dogs of folklore.

Many believe big cats are supernatural in some way as their bodies are never found by the roadside as with other roadkill.

She said: "They could be creatures from another world. I don't think they're ghosts. That's one of the mysteries that we don't find bodies."

Big Cats in Britain (BCIB) which is staging the Watchet conference, says last year it logged 675 reports of big cats across the UK with 12 reportedly spotted in Dorset and six in Hampshire. The top place for sightings was Yorkshire with 64, Devon was second with 38 and 37 sightings in Somerset.

Big cat expert Jonathan McGowan, a zoologist at Bournemouth Natural Science Society, is convinced that the creatures are living breathing animals.

Jonathan based in Bournemouth spends much of his time tracking big cats across Dorset collecting evidence of the creatures' existence.

He said: "I think they are biological living animals. I've been studying them for the last 20 years. At the moment I have just been tracking one of my leopards in Studland. I have got a lot of evidence of leopards, lynx and puma but also other types of cats."

The reason why bodies of big cats struck by cars are never found by the roadside is because Defra and the Environment Agency quickly moves the bodies he says.

"They realise if people knew the truth there would be outrage. I have got photos of lynx shot by gamekeepers and two Lynx were run over in Dorset recently.

"I find signs everywhere. I have got photographs of footprints and deer killed in a particular way and lots of droppings that go in my freezer for analysis.

"Cats are mainly nocturnal. They can see you coming miles away and I have so much evidence on video camera."

If big cats do exist they should be "protected" as they are much needed in our ecosystem he adds.

"It's not bad. It's good. We've needed these animals in our ecosystem keeping down the numbers of foxes and deer. The more evidence we can give to the Authorities the more chance there is that something will be done to protect them," he said.