Three swimmers who jumped off structures into the sea were seriously injured in separate incidents on Saturday.

Coastguards said "tomb stoning" into water was extremely dangerous.

A man suffered suspected head and neck injuries after jumping from the western breakwater of Brighton Marina at about 1.45pm.

Thirty minutes later another man, aged 30, was taken to Royal Sussex County Hospital with neck and back injuries after jumping from Palace Pier, Brighton.

And coastguards helped recover a 13-year-old boy from rocks at 7.45pm after he had been jumping off the breakwater at the entrance to Shoreham Harbour with a group of friends.

The teenager was treated at Worthing Hospital for suspected head, neck and spinal injuries, and was released later that night.

Dave Cassan, of Shoreham Harbour Lifeboat, said the teenager was the lifeboat's first casualty of the summer.

He said: "The boy dragged himself up a ladder and then passed out. If he had lost consciousness in the water, he would have drowned. He was treated for more than an hour by paramedics.

Mike Greiner, of Solent Maritime Rescue Co-ordination Centre, said the rise in the number of people jumping into the sea was concerning and urged people to use common sense.

He said: "It is very hard to judge the depth of water due to swell and sea conditions.

"Serious injuries often resulting in loss of life are often sustained when hitting the seabed or an underwater obstruction."