Queen and Castro had hoax calls
Hoax calls have a long history of embarrassing politicians and royalty - but can also end in tragedy when the joke gets out of hand.
Often used by radio DJs, pranks have caught out the likes of the Queen, late pope John Paul II and even Cuban president Fidel Castro.
And this weekend's call to David Cameron was not the first time an imposter has managed to get through to a prime minister at Downing Street.
Radio stunt merchant Steve Penk played the trick on Tony Blair as he left his morning briefing in 1998 with the help of i mpressionist Jon Culshaw.
Culshaw put on the voice of then-leader of the opposition William Hague and offered the prime minister a Cher exercise video.
Taking the joke in good jest, Mr Blair laughed along and said: "That's quite a good imitation."
What gave the game away was that Culshaw called him "Tony", whereas Mr Hague would always have used "prime minister".
One of the most famous hoax calls ever staged came some three years earlier when the Queen chatted on air to a Canadian DJ pretending to be Canadian prime minister Jean Chretien.
Pierre Brassard got through to Buckingham Palace, spoke to the monarch on-air for 15 minutes and elicited a promise for her to influence Quebec's referendum on proposals to break away from Canada.
The Queen fell hook, line and sinker for the ruse, with the Palace later describing the incident as "irritating and regrettable".
On another occasion, Brassard spoke to pope John Paul II, asking the pontiff if he had ever thought of fixing a toy propeller to his cap.
In 2003, Miami radio station El Zol spoke to late Venezuelan president Hugo Chavez pretending to be Cuban president Fidel Castro before reversing the prank by calling Castro posing as Chavez.
Castro famously lost his temper and swore at the DJs live on air after they revealed that "the whole of Miami" had been listening in on the joke.
Sadly, one of the most recent pranks to make headlines led to the death of a nurse at a hospital where the Duchess of Cambridge was being treated for morning sickness.
Australian shock jocks Mel Greig and Mike Christian called King Edward VII hospital impersonated the Queen and Prince Charles to ask staff questions about the Duchess's health.
Indian-born nurse Jacintha Saldanha, who transferred the call to a duty nurse, was found dead three days after the prank was broadcast in December 2012.