Pet cats are turning feral and growing to more than 4ft in the wild, a British professor has claimed.
Stephen Harris, professor of environmental sciences at Bristol University, said that since wolves and other large animals had become extinct in the UK, a gap had opened for a large predator.
He believes the niche could be being filled by previously domesticated cats which have turned feral and grown to large sizes.
It may explain sightings of the so-called Essex lion which was apparently spotted in Clacton-on-sea over the weekend.
While lions, leopards and pumas are unlikely to be found on the prowl in Britain, a number of pet cats turned feral could be causing the confusion, claims Professor Harris.
The domestic animals can be as long as 4ft from nose to tip of tail in Britain and Mr Harris claimed he had seen domestic cats growing to more than 5ft in Australia.
Prof Harris, said: “There are no leopards or pumas out there but we do have a population of feral cats – domestic cats that have gone wild – and some of them are getting surprisingly large.
“They’re living by themselves, no-one is responsible for them.”
Unlike in Australia, where the animals are considered to be pests and are shot dead and measured, here their size tends to be assessed less scientifically, by comparing them to the background they are spotted against, he said.
“I don’t think these pose a threat to anyone,” Prof Harris told Radio 4’s Today programme.
But he suggested they could fill the gap vacated by wolves in this country as there are no longer any big predators roaming in the wild here.
His comments came after residents and holidaymakers reported seeing what they took to be an escaped lion on the loose in the tiny Essex village of St Osyth over the weekend.
The beast was spotted in a field on Sunday and captured in grainy mobile phone footage, which left most people none the wiser as to its identity.
The claims sparked a major police operation and panic among locals.
But by yesterday the “lion” had been downgraded to a large domestic cat, possibly called Tom or Teddy Bear.
It is believed a pet sparked the scare and a list of possible candidates was being compiled.
One of the pictures shown to police by Stephen and Gill Atkin, who had thought they had seen a lion