Police are investigating after a milkman claimed he saw a huge black panther-like cat on a street in Sussex.

He said he saw the mystery beast loping along Southdown Road in Portslade while he was delivering in the early hours of yesterday morning.

The calls, shortly before 3.30am, prompted police to send out a search team that scoured the area but failed to find the big cat.

However, officers are investigating as there were reports a woman had seen a similar animal in Hove within the past fortnight.

A Sussex Police spokesman said: "The caller said he saw the panther in his headlights and someone else at the scene had seen it too. He also mentioned the lady in Hove.

"We take these things seriously in the sense that the animals could be a danger to themselves or to the public."

Big cat experts are certain felines such as panthers, lynx and leopards are living wild in Sussex.

They believe the creatures have been at large since a government crackdown on keeping wild animals as pets, which has lead to people releasing them into the countryside.

The Panther of Portslade is not the only reported sighting in the county. Big cats have previously been reported seen in Lewes, East Chiltington and Ashurst, near Henfield, as well as on the outskirts of Brighton.

The 700-member British Big Cats Society, which investigates sightings, received nine calls from Sussex last year, out of 1,077 from across Britain.

The previous year, there was only one report from the county.

Society leaders believe for every big cat sighting that gets reported, there are two or three that do not.

Society founder Danny Bamping said: "It is no surprise that big cats are being seen in Sussex, particularly with a lot of rural areas nearby.

"People should not go near any big cats they see because they are potentially dangerous but we do not want them captured.

"Our core aims are to prove and to protect. It is great to have them back in Britain."

Jeremy Adams, curator of the Booth Museum of Natural History in Dyke Road, Brighton, said: "There have been a number of sightings over the years but they have never been verified with a body.

"The nearest were a couple of medium-sized cats that were found near Chichester.

"There have been so many reports, I think there has to be some factual basis but some evidence is required, really."

One theory holds that the big cats have been breeding in the wild since the 1976 Dangerous Animals Act banned people from keeping exotic animals without a licence.

For more details about the British Big Cats Society, visit www.britishbigcats.org