A 'big cat' expert fears trophy hunters will flock to kill them - after new DNA evidence confirmed their existence in the UK.
Frank Tunbridge, 74, says the latest findings could also cause the public to 'panic' and put pressure on councils to cull the animals.
Documentary makers revealed last week they had received a 99% match on a hair sample found on a fence to a big cat species.
Frank, who has studied big cats for over 60 years, fears the new evidence will endanger the species - and make them targets for bounty hunters.
Frank, from Podsmead, Gloucestershire, said: "Big cats have been out there for 40 odd years now.
''They keep themselves to themselves and they haven't harmed anyone ever.
"The DNA confirmation is a double edged sword.
''On the one hand I think more people will come forward with really good images now it's been verified.
"But I also fear that there we will suddenly get bounty hunters most probably coming out of the woodwork shooting them.
"With trophy hunters, they won't just want a blurry photo. They'll want something more realistic to show their friends."
Frank, who runs a big cat sighting hotline, is also concerned that panic from the public will force authorities to step in and disturb the animals.
He added: "The public panic a lot. Now they know they're out there they wont want to take their kids or dogs for a walk.
"This will make them pressurize the local council who might try and control the animals by trapping them or even eradicating them.
"Unfortunately, if the police realise there's something potentially dangerous out there they'll have to have a contingency plan - even though the big cats never hurt anyone."
Frank has been studying big cats and wildlife for "most of his life".
He receives an average of three calls reporting big cat sightings a month, but is confident that big cats are not dangerous to the British public.
It is widely believed that big cats, amongst other exotic animals, were released into the wild in Britain following the Dangerous Wild Animals Act 1976.
This act ensured that if individuals kept dangerous wild animals, they did so in a way that posed no risk to the public and which safeguarded the welfare of the animals.
It is thought that many owners of exotic pets - including big cats - release them into the wild soon after.
Frank said: "Big cats have been out there for years. They keep themselves to themselves and they haven't harmed anyone.
"You can go anywhere in the world and these animals will avoid humans. They don't like us.
"I think people should just accept them, but I'm not sure they will. They're here now, and to trap or kill them or put them in a zoo would be terrible.
"In all my years of doing this, I haven't heard one report of someone getting hurt. They do sometimes follow people with small dogs because they're curious but that's all.
"They're helpful for keeping the deer population at bay and they're not going to go away now.
"Instead of panicking, we need to learn to live with them."
