David Cameron apologised on Wednesday for revealing a private conversation with the Queen which took place following the Scottish independence referendum.
The Prime Minister said that he was "extremely sorry" and "very embarrassed" after he was overheard on microphone telling Michael Bloomberg, the former mayor of New York, the Queen's reaction to the No vote.
He also said that he intends to apologise personally to the monarch in Buckingham Palace. He said: "Look, I'm very embarrassed by this. I'm extremely sorry about it.
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"It was a private conversation, but clearly a private conversation that I shouldn't have had and won't have again.
"My office has already been in touch with the Palace to make that clear and I will do so as well."
Mr Cameron was unwittingly overheard speaking to New York's former mayor on Tuesday when the pair entered the headquarters of Bloomberg.
The two politicians were being filmed as they walked through the building, but were unaware that their conversation would be picked up by microphones.
He said: "The definition of relief is being the Prime Minister of the United Kingdom and ringing the Queen and saying 'It's all right, it's OK'. That was something. She purred down the line."
The Queen remained politically neutral throughout the campaign in the run-up to the referendum held last week, until closer to the vote, when she said that people should "think very carefully" before they voted.
The historic referendum resulted in Scotland remaining a part of the United Kingdom, by a margin of 55 per cent to 45 per cent.