A man has been attacked by a large cat-like animal which jumped out from bushes in his garden during the night.
The victim described a "big black figure" pouncing on him
Anthony Holder said a 6ft-long black animal pounced, knocked him to the ground, then mauled him with its claws for about 30 seconds.
He said "I am 6ft and weigh 15 stone and it was considerably stronger and bigger than me. This thing was huge."
Police were called to Sydenham Park in south-east London and one officer saw a cat "about the size of a Labrador dog".
Armed officers arrived soon after and a search of the nearby railway line and allotments was carried out.
Mr Holder was looking for his kitten at the bottom of his garden, which backs onto woodland, when the powerful creature attacked him.
He described how a "big black figure pounced" and he was "in its claws for about 30 seconds".
"Its teeth were out and I tried to defend myself and eventually I got the thing off my body."
He was scratched all over his body and suffered swelling and bruising to his hand and the back of his head.
The animal, which Mr Holder is convinced was a panther, then went and sat in the garden next-door, and he called the police
The Metropolitan Police have mounted extra patrols in the area, which is largely residential and backs on to a railway line.
They have warned people not to approach the animal and to keep pets inside.
The RSPCA and London Zoo are being consulted for specialist advice.
Inquiries are also being made to trace exactly where the animal may have come from.