Staithes lifeboat was launched at 10.40pm on Monday night when four teenagers became trapped by the sea beneath cliffs near Skinningrove.

The volunteer lifeboat crew was called after one of the teenagers managed to phone the police to say they were surrounded by water to the south of Skinningrove.

A mobile coastguard team and the police helicopter were also deployed.

When the lifeboat arrived on scene they found the group, which included two male and two female 17 and 18-year-olds, perched on a ledge six feet above the water.

One of the lifeboat crew swam ashore and it was discovered one of the youths had fallen into the sea while trying to get to safety.

The 17-year-old was showing signs of hypothermia and it was decided he needed to be evacuated immediately.

He was put into to the lifeboat and taken to a waiting doctor and ambulance at Staithes, arriving at 11.40pm.

By this time the tide had started to go out and Skinningrove coastguard teams managed to reach the three remaining casualties on foot.

They were then walked back to Skinningrove under the watchful eye of police helicopter India 55.

James Austin, the lifeboat crewman who swam ashore, said: "Despite the fine weather on Monday night there was quite a swell at the scene and the area is very rocky.

"This meant the lifeboat had to anchor and I swam ashore with a line, something we practise all the time.

"The group were all scared but the guy who had fallen in was obviously wet and very cold.

"The three others were still dry and the tide was starting to go out so we decided to take the hypothermic casualty back to the doctor at Staithes."

By half past midnight the remainder of the group was safely ashore and the rescue teams were stood down.

The cold casualty made a full recovery.