Teenagers are dicing with death as they leap into the sea from harbour walls in a dangerous annual craze.

Youths are jumping into the water from Brighton Marina and the Palace Pier in Brighton.

Every year, warnings from coastguards and seafront officials warn jumpers against taking the risk, which officials say is "insane".

Yesterday youths flung themselves from the pier, nearby groynes and the breakwater at the Marina, ignoring advice from coastguards and lifeguards.

Nigel Guyll of the Solent Coastguard said: "They are risking their lives. When they start jumping off the water may be high but as time goes on the tide will go out and the rocks are just under the surface.

"The people who do it just don't listen to us. They'll only stop doing it if the police get involved."

Officials at the Marina called the coastguards out to try to stop a group of people jumping from the breakwater.

They remonstrated with them but they would not leave until police officers arrived.

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

This year Sussex Police also have powers to move on groups of people around the Palace Pier who are behaving anti-socially or causing an annoyance.

The new city-wide dispersal orders mean they can tell people diving off the pier or the nearby groins to leave the area for 24 hours if they are likely to cause problems for the coastguards.

Viki Miller, a seafront officer, said: "The police have already used the order twice to stop people jumping so we hope its going to make a difference.

"The jumpers are a danger to themselves and the public. No-one has been injured yet this year but it is always a risk."

With temperatures expected to hit 28C (82F) today there are likely to be more divers attempting the foolhardy stunt.

Mr Guyll said: "The trouble is it is not against the law to jump into the sea from a height. We get abuse sometimes from the people doing it when we tell them of the dangers."

Two 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 in The Argus 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.

He had to be rescued from the sea and taken to hospital.

Last year the Royal Society for the Prevention of Accidents (RoSPA) published figures showing that the number of swimmers who drown off the coast of Sussex each summer had tripled from five in 2000 to 15 in 2002.

Another 12 people drowned in the heatwave of July and August 2003.