Cornwall’s harbourmasters have warned against the dangers of ‘tombstoning’ that has reached "epidemic proportions."

Tombstoning involves jumping off cliffs, seawalls and harbours into deep water, but has claimed 20 lives across the UK since 2007.

Now Truro and Penryn Harbourmaster Mark Killingback, who has worked closely with HM Coastguard and police over many years to highlight the dangers, has added his voice to calls to stop this high-risk activity.

Mark said: “With better weather, and everyone flocking back to the coast, tombstoning has again reached epidemic proportions.

“We cannot over-emphasise how dangerous it is to - quite literally - jump into the unknown. You can never tell what is hidden from view under the sea’s surface.

"Not only hidden rocks, but we have pulled out rusting bicycles and wooden stakes from water adjacent to harbour walls – imagine the injuries they could cause."

He said since 2004 the coastguard has dealt with over 200 incidents, with 70 injuries and 20 deaths, adding: "This is completely unnecessary risk-taking.”

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The Safer Cornwall partnership, which includes Cornwall Council and Devon and Cornwall Police, has reminded parents to keep track of their children’s activities.

They have had reports of anti-social behaviour associated with tombstoning, including people being threatening or abusive, alcohol consumption and criminal damage.

Newquay and St Ives Harbourmaster Mike Ridgway said there have been reports on the rise of tombstoners being verbally abusive to boat skippers, who sound their horns as a warning to move out of the way when they are entering the harbour.

In Penzance there has been tombstoning from quays and from the stern of the Scillonian ferry, as well as swimming in the harbour mouth while vessels are approaching.

Chris King is pier master of Falmouth’s Prince of Wales Pier and has recorded numerous incidents of tombstoning during May and June this year, including one where damage was done to one of the pier buildings.

Rob Nolan, Cornwall Council’s cabinet member for environment and public protection, said: “Tombstoning can have severe and life-threatening consequences. We’re urging everyone to consider the risks to themselves and others. Look out for warning signs and don’t jump into the unknown.”

To report any anti-social behaviour ring the police on the non-emergency number 101 or email 101@devonandcornwall.pnn.police.uk

It can also be reported to Cornwall Council’s Anti-social Behaviour Team on 0300 1234 232 or at antisocialbehaviour@cornwall.gov.uk

If the threat is causing immediate danger call 999.

For more information visit the Safer Cornwall website.