A YOUNG man spotted struggling in the sea off Old Harry Rocks is lucky to be alive after being rescued by the RNLI, who just by chance were on exercise nearby.

Lifeboatmen say the man, who had walked out to Old Harry earlier at low tide from Knoll beach, would most likely have been swept out to sea if they hadn't noticed him.

He had no means of raising the alarm, and had been attempting to swim against the flood tide for three-quarters of an hour when he was rescued.

Poole inshore lifeboat volunteer RNLI helmsman Glen Mallen said: "He was extremely lucky that we were in the right place at the right time, with the sea and tide conditions shifting, he would have found it difficult to get back to shore."

The man, who was later reunited, unharmed, with friends on Knowle beach, was 300 metres from the cliff face when Mr Mallen spotted him.

The Poole inshore lifeboat was on exercise in Poole Harbour on Wednesday evening, with a group of young people working towards their Duke of Edinburgh awards.

It was a spur of the moment decision, say the lifeboat crew, to take advantage of the conditions outside the harbour - the lifeboat crew opted to practise their 'man overboard' exercise before heading west for some marine manoeuvres.

It was while carrying out manoeuvres quarter of a mile off Old Harry Rocks, that Mr Mallen caught a glimpse of the person in the water.

An RNLI spokesman explained: "The person was some 300 metres from the cliff face, trying to swim. It was the last of the flood tide, with the tide just about to turn. For certain the young man would have been taken out to sea.

"The volunteers took him onboard and checked he was okay, then took him ashore back to Knoll beach, where they met up with coastguards."

Mr Mallen added: "It is so important to have some means of communication so that you can call for help and an understanding of the state of the tide and the sea conditions."