Thrill seekers are being warned of the dangers of tombstoning as popular holiday hotspots prepare to welcome tourists back after the coronavirus lockdown.
Jumping from a cliff or pier into water can result in serious injury or even death, and 20 people have been killed since 2007.
In recent weeks, three people were hurt after leaping 200 feet from the cliffs at Durdle Door in Dorset into the sea.
Now there are fears that tombstoning will be on the rise in Cornwall as holiday destinations prepare to welcome guests from the weekend.
Truro and Penryn harbourmaster Mark Killingback, who has worked closely with HM Coastguard and police over many years to highlight the dangers, 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.
“Since 2004 the Coastguard has dealt with over 200 incidents, with 70 injuries and 20 deaths.”
He added: “This is completely unnecessary risk-taking.”
The Safer Cornwall partnership, which includes Cornwall Council and Devon and Cornwall Police, said it had received 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 of tombstoners verbally abusing 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.
Councillor 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.”