Teenagers were seen jumping off cliffs in Marsden – just yards from the spot where teenager Jamie Sutton died in May while taking part in the deadly craze.

The Maritime and Coastguard Agency recently launched a campaign called Don't Jump Into the Unknown, and today it renewed its warning to youngsters not to put their lives at risk.

Greg Albrighton, the borough's sector manager for the agency, said: "I'm not surprised that this is still happening, as we don't expect results overnight.

"What we are trying to do is educate children and young adults about the dangers they are putting themselves in.

"Of course, young people always take risk – it's a kind of rite of passage – but they need to stop and think 'will this risk cripple me for the rest of my life?'

"If we can stop one person from doing it, then hopefully it will lead to more."

Nine lives have been claimed across the UK by tombstoning in the last two years, and hundreds more people have been injured.

In May, 17-year-old Jamie died after leaping from cliffs near Souter Lighthouse at Whitburn.

Agency spokesman Mark Clark added: "Youngsters do not understand the dangers of the tide.

"I have been to speak with family and friends of people who have injured themselves, and the effects on families are devastating.

"All of the parents' hopes and dreams for their children are dashed, and for what? A moment of stupidity.

"If you want to get the high or buzz from jumping, go to a swimming pool with a high board or enrol on a diving course. Do it safely."

The Don't Jump Into the Unknown campaign is run in partnership with the Royal National Lifeboat Institution (RNLI) and the Royal Society for the Prevention of Accidents.

Together, they are working with councils to raise awareness through educational initiatives.

An RNLI spokeswoman said: 'Tombstoning is a high-risk activity which has resulted in a number of fatal accidents, including one in Whitburn just a few weeks ago.

"We would urge anyone considering taking part to think again.

"Jumping from any height is always dangerous, but add in the unpredictable nature of the sea and the fact that the climb back out may be just as hazardous as the descent, and it is quite clear why we don't want people to tombstone."

Posters put up as part of the campaign feature a special barcode which allows people with Internet-enabled phones to access a website on the dangers of tombstoning.