Australian John van Wisse has encountered an unexpected obstacle in his ambitious ultra-triathlon bid from London to Paris - the British border patrol.
The Melbourne athlete, who is on track to break the record for one of the world's toughest sporting challenges, was briefly mistaken for an illegal immigrant as he prepared to begin the swim leg across the English Channel on Wednesday.
Police and coast guards were called to Dover's Shakespeare Beach by concerned locals around 8.30am but quickly saw the funny side when they realised what they were dealing with.
A Kent Police spokeswoman told the Dover Express it appears some people called police, thinking it was illegal immigrants coming ashore after several people were seen jumping off a boat.
One eyewitness told Dover Express: "He'd jumped in and out of the water from a boat posing for pictures.
"We were only there around 15 minutes before the police turned up. They were walking up and down the beach thinking it was an illegal immigrant.
"It was hilarious and the police saw the funny side."
Kent Police said: "It looks like a couple of people called thinking it was illegal immigrants coming ashore because some people were seen jumping off a boat.
"The Border Force were down there and the Coastguard but it was a Channel swimmer."
Van Wisse, 41, on Tuesday set off on the "Arch to Arc" challenge, from London's Marble Arch to the Arc de Triomphe in Paris.
He had already run 138 kilometres from London to Dover when confronted by police before embarking on a 34km swim to France across the English Channel. The final leg is a 290km bike ride from the Channel coast to Paris.
Van Wisse is attempting to break the record of Mark Bayliss of Great Britain who completed the London to Paris challenge in 73 hours and 39 minutes in 2012 including waiting 14 hours on the English coast for the optimum tide for the Channel swim.
According to News Corp reports Van Wisse overnight was just half an hour from the French coast.
Van Wisse, 41, told News Corp before the race that weather conditions gave him little room for error in crossing the English Channel.
"It is a big leap of faith in my swim coach Mike Oran who has a lot of experience with the Channel swims," he said. "Once I start the run, even if the weather is bad, I can't turn back because the clock has already started," he said.
AAP with Fairfax Media