Explorer Robin Hanbury-Tenison has been unsuccessful in his bid to become the oldest person to water-ski across the English Channel.
The 79-year-old left the shores of Dover, Kent, at about 6.30am today for the last of eight challenges he set himself ahead of his 80th birthday next May.
But unfavourable weather conditions created waves much bigger than anticipated in the Channel, forcing Mr Hanbury-Tenison to abandon his attempt.
He said: "We thought we had a hole in the weather but it wasn't as good as everybody had hoped. I got up but the conditions were what one of the people described as 'boat breaking'.
"I didn't get very far and realised that I wasn't going to make it. There was no way that I was going to fight those waves for an hour and a half."
Mr Hanbury-Tenison set himself the eight challenges - one for each decade of his life - to raise funds for Survival International, the global movement for tribal people's rights which he co-founded in 1969.
His other stunts included skydiving from 14,000ft over Cornwall, climbing the four highest mountains in Britain, running the London Marathon and cave abseiling down the Titan shaft in the Peak District.
He left Dover with 13-year-old Lauren Bird, who got just under halfway across in her bid to become the youngest person to water-ski across the Channel.
Her father Steve, from Burnham-on-Sea, Somerset, said: "She was doing really well in really taxing conditions, but some of the waves were bigger than her, and she's quite small."
Mr Hanbury-Tenison has raised more than £60,000 of his £80,000 target.
Although he does not plan to repeat the Channel attempt, he does aim to prove he can complete the distance by water-skiing 20 miles on an estuary in Rock, Cornwall, close to where he lives.