David Cameron postponed a phone call from Barack Obama to secure victory in a game of tennis, according to one of his friends.
The claim was made by Charlie Brooks – who went to Eton with the Prime Minister and is married to former News of the World editor Rebekah Brooks.
Racehorse breeder Charlie told the Racing Post : "I played tennis with him at Chequers one day.
"I won the first set easily, then he won the second set, and then someone came up to him and said 'er ... Mr Obama is on the phone for you, Prime Minister'.
"I thought 'okay, we'll have to leave it there'. But he said 'I think we've got time for a third set - tell Mr Obama I'll ring him back'.
"He obviously thought he had me on the ropes. And I beat him two sets to one."
Downing Street has said the pair only played tennis at Chequers once, and that no phone call was logged from the US commander-in-chief during that time.
Meanwhile, Gordon Brown's former spokesman Damian McBride suggested that there was a logical explanation for the contradictory claims.
"I'm guessing Obama wasn't really on the phone and that's just the pre agreed 'out' the clerks always give Cam once a meeting has run an hour," he tweeted.
Mr Cameron's passion for tennis is well documented, and a recent biography cited it as one of the ways the British leader disconnects from the pressures of his job.
Karaoke, snooker, and several glasses of wine with Sunday lunch were also listed as favourite pastimes.
In the book Cameron: Practically a Conservative, a colleague is quoted as saying: "If there was an Olympic gold medal for 'chillaxing', he (Mr Cameron) would win it."