A man was picked up seven miles from the UK coastline on a stand-up paddleboard, wearing just a hat, fleece and shorts.
The nature of the paddleboarder's reason for being at sea remains unclear, with conflicting reports from eyewitnesses and Government officials.
The man, an EU national who has not been named, was spotted by divers off the coast of Dover at dawn on Sunday.
A Home Office spokesman said the man had become disorientated on his paddleboard.
He said: "The man was a German tourist in distress but who was in the country legally - he was not an illegal immigrant.
"He had been on the water for some time having gone out on his paddleboard and was picked up by HMS Valiant."
Nigel Scutt, a marine researcher who runs the Dover-Marina.com website, said: "He said he had made his way across the Channel from France, leaving at about midnight.
"The divers saw him at about 7.30am, so he was probably just over halfway towards the UK.
"There is quite a lot of this going on, but it is a polarising issue so the Government does not want it known."