A WARNING has been issued after a rogue jet ski was seen blasting across the water with no one riding it.

The RNLI spotted a jet ski due south while on a training exercise on Wednesday evening and managed to cut its engine before searching for the missing rider.

The man had fallen from the vehicle while travelling at 40 miles per hour, and thanks to his life jacket was quickly found in the water by the crew.

He was conscious and taken to Brighton Marina lifeboat station.

Lifeboat operations manager Roger Cohen MBE said the man had a “lucky escape with some minor bruising”.

“This is exactly what we train for and I'm proud of the team recognising that there was something amiss with the jet ski and quickly finding the rider,” he said.

But the RNLI always recommends wearing a kill cord which will cut the engine should the driver fall off.

The Argus: The driverless jet ski returning to shore. Photo: Brighton RNLIThe driverless jet ski returning to shore. Photo: Brighton RNLI

It also advises people to carry a means of calling for help.

“This incident highlights the importance of a fully operational kill cord being on board a watercraft and used correctly,” said Mr Cohen.

“The RNLI recommends that before any watercrafts that are equipped with a kill cord are taken to sea, the operator should deliberately operate the kill cord to confirm it is operating correctly.”

Other precautions include telling someone where you are going before you head out, checking the weather forecast and tide time, ensuring your jet ski has enough fuel, checking your equipment works properly, and to always wear a life jacket.

It comes as the RNLI also issued a statement on tombstoning – or jumping into water from a height.

While the RNLI does not advocate people tombstoning, it said people who do can take steps to reduce the risk of injury, which include checking for hazards in the water like submerged rocks, checking for access to ensure they can get out of the water, and never entering the water under the influence of alcohol, drugs, or peer pressure.

The charity is also urging anyone visiting the coast this summer to make sure they keep themselves and their families safe by swimming in between the red and yellow flags at lifeguarded beaches.