David Cameron has been recorded apparently revealing in a conversation that the Queen "purred" when he told her Scotland had voted against independence. It's by no means the first time a politician has been caught out in this way.

2010: Bigotgate

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Oh dear. This was just about as embarrassing as it gets. Gordon Brown pronounced himself to be "mortified" after he was picked up referring to Labour supporter Gillian Duffy, with whom he had been discussing immigration, as "bigoted". While out on the general election campaign trail, he had left a microphone on as he entered his car following a walkabout. The then Labour PM swiftly performed a humiliating penance, travelling to Mrs Duffy's house in Rochdale to apologise.

He was none too happy when the remarks were replayed to him while doing a radio interview.

2006: Yo, Blair

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US President George Bush's exchanges with UK Prime Minister Tony were recorded at a G8 summit in Russia. They began with Mr Bush apparently asking: "Yo, Blair. How are you doing?" Critics said this was over-familiar and showed a lack of respect on the part of the leader of the free world for his ally. Mr Blair ended the eavesdropping when he spotted the live microphone and switched it off.

2005: Mad cow disease

Image copyright Getty Images Image caption What about the beer, Monsieur le President?

Former French President Jacques Chirac had a fractious relationship with Mr Blair. Speaking to German and Russian leaders, he revealed a level of distaste over more to do with Britain. "After Finland, it is the country with the worst food," he said, adding: "One cannot trust people whose cuisine is so bad." He also said: "The only thing they have ever done for European agriculture is mad cow disease." The UK government failed to bite, a spokesman remarking: "There are some things that it is better not to comment on."

1993: Angry Major

People remember Conservative John Major as one of the milder-mannered prime ministers in British history. But, back in 1993, he was an angry man. Embroiled in battles with the more Eurosceptic of his cabinet ministers, he spoke honestly about his feelings to ITN's Michael Brunson. Unaware that he was still being recorded after an interview, Mr Major described his foes as "bastards" he would like to "crucify".

1984: Reagan's revelations

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Rivalling even the later intensity of ill-feeling between Mr Major and some of his colleagues, US President Ronald Reagan gave jokey vent to a few of his own Cold War opinions. While warming up for his weekly radio address, he practised with an incendiary line which might actually have been a potential vote-winner: "My fellow Americans, I'm pleased to tell you today that I've signed legislation that will outlaw Russia forever. We begin bombing in five minutes."