Sunbathers watched in horror as thrill-seekers threw themselves off a pier in a dangerous annual craze.

Labourer James Clark was snapped performing a double somersault off the Palace Pier in Brighton yesterday.

Police and coastguards have warned of the lunacy of the pastime, nicknamed tombstoning, in which children as young as 11 take part.

As temperatures continue to soar they fear more people will follow the example set by Mr Clark of Islingword Road, Brighton.

Mr Clark, 18, however, was defiant.

He said he and his friends had been jumping from the pier for several years and knew of the potential dangers.

He had winded himself when he first attempted to perform a stunt and landed on his stomach in the sea.

He said: "I suppose it could be a bit dangerous but we know what we are doing and what to look out for.

"We just enjoy it, especially in the summer. The hot weather makes it all the more encouraging.

"There are signs telling people not to do it but we know the danger areas. I would warn other people not to do it if they are unsure about what they are doing."

A police spokesman warned jumpers the quick adrenaline rush could have serious consequences.

He said: "It is extremely dangerous because you don't know what you are jumping into or what lies underneath.

"People have seriously injured themselves in the past and we would advise them not to do this.

"It is only a matter of time before someone is seriously hurt. Tombstoning is a horrible but appropriate name for something so deadly."

Geoff Matthews, watch officer at Solent Coastguard, said sunbathers had begun to report tombstoning this season.

He said: "We have to get people down there to try to talk to them when our resources could be used better elsewhere.

"There are strong currents and tidal patterns near structures in the sea which are exceedingly dangerous. There is a great deal of fun to be had at the seaside and you don't have to throw yourself off a pier to have it."

Three years ago, the daredevil craze took on a dangerous new twist when teenagers began jumping from the top of the Palace Pier helter-skelter.

Police and coastguards appealed for them to stop making the 50ft leap but the lunacy continued in the summer of 2004 when a man in his 20s was knocked unconscious after diving from the roof of a pier building.

A teenage boy also suffered back and neck injuries when he jumped off the Palace Pier last August.

Warning signs have been put up by Brighton and Hove City Council's seafront office to deter the jumpers.