Sir Richard Branson has challenged a New Zealand businessman's claim to have set a new record for an English Channel crossing in an amphibious vehicle.
Sir Richard Branson set a world record in the Aquada in June 2004
Nick Fox, who lives in London, travelled from England to France in 43 minutes and 12 seconds on Tuesday.
Sir Richard entered the record books in 2004 when his car-boat made the crossing in a little over 1hr 40mins.
However, he has questioned whether Mr Fox's vehicle qualifies as amphibious because it only goes slowly on land.
"They've obviously done an incredibly fast crossing of the Channel," admitted Sir Richard.
"Whether it is an amphibian vehicle I'm not quite sure, that would be for the Guinness Book of Records to decide."
His argument is that Mr Fox's Sealeg boat - which has three wheels that retract on entry into the water - can only travel at speeds of around 5mph on land.
"The car-boat that we were in [the Gibbs Aquada] was a proper car that went 120mph on land and also was a proper boat when it was on water."
A champagne celebration in France for Nick Fox and his crew
The Sealeg, invented in New Zealand, can travel at speeds of up to 35 knots on the sea.
It was launched from the Dover slipway in Kent and landed in Cap Gris Nez near Calais on Tuesday.
Mr Fox and his crew are already celebrating a new world record, although the time and their vehicle type still have to be verified by the Guinness Book of Records.
Responding to Sir Richard's comments, Mr Fox said: "It's not a car. It is mainly an amphibious boat but it can drive itself in and out of the sea and that's what makes it count as an amphibious vehicle."
The Virgin chief insisted it was not a case of sour grapes.
"If they've beaten our record we'll certainly be out there again seeing if we can wrench it back from them. We had a lot of fun doing the Channel crossing."