Seasick-prone Sean Conway sailing bid under way

The three-man crew had to sail seven hours from Falmouth to the starting line at Land's End

An extreme adventurer is aiming to be the first person to run, swim, cycle and sail the length of Britain.

Sean Conway's fourth foray began earlier on Friday and involves sailing from Land's End to John O'Groats along the west coast within 72 hours.

Mr Conway said: "I am not really a sailor and I get really sea sick."

The Cheltenham adventurer finished the third stage of his "ultimate triathlon" - running 1,000 miles from Caithness to the Cornish landmark - in May.

'Pretty rustic'

His other adventures have been self-supported, but this time he is being joined by two experienced sailors, skipper Phil Sharp and Alex Alley.

Jersey sailor Mr Sharp is using the challenge as part of his training for next year's round the world solo race, the Vendee Globe.

As the sailing journey is during December, the crew are expecting some rough, stormy seas.

"By the time we get around Skye and into the Hebrides there's a good chance we will get into some horrible headwinds," said Mr Conway.

Phil Sharp, (l), and Alex Alley are the experienced sailors helping Sean Conway

The vessel is a 40 ft purpose-built race boat but has few home comforts.

"There's no toilet, so it's bucket and chuck it," explained Mr Conway.

"Our cooking facilities are a little stove, barely a bunk bed, so it is pretty rustic."

The crew sailed seven hours from Falmouth to get to the start line at Land's End for 08:55 GMT when the record attempt officially began on Friday.

They hope to arrive at their finishing line by Tuesday morning at the latest.

Sean Conway successfully ran the length of Britain earlier this year