David Cameron
Prime Minister David Cameron said he is extremely sorry about his description of the Queen's response to the Scottish referendumReuters

David Cameron has issued an apology to the Queen after saying she "purred down the line" when she reacted to the Scottish referendum result last week.

The Prime Minister was accidentally heard boasting to billionaire media mogul, Michael Bloomberg, about his jubilation at ringing the Queen to tell her Scotland had decided to stay with the UK.

His comments were recorded by a TV crew while he was in New York for the United Nations General Assembly meeting,

He said: "The definition of relief is being the Prime Minister of the United Kingdom and ringing the Queen and saying, 'It's alright, it's okay'. That was something. She purred down the line."

Alex Salmond, former SNP leader, condemned his actions as "absolutely pathetic" and that Cameron should "hang his head in shame".

Cameron has contacted Buckingham Palace to apologise to the Queen and will do so in person when he meets her next, a Downing Street spokesman said.

When asked recently if he regretted his comments to Bloomberg.

He said: "Yes and yes. I'm very embarrassed about this, I'm extremely sorry about it. It was a private conversation, but clearly a private conversation I shouldn't have had and it won't happen again."

Dr Andrew Smith, teaching fellow of modern history at University College London, said: "It was very naive not to think there was a chance of the conversation being picked up... given his choice of language, the description of her purring, and the fact that there is an important constitutional convention here, I have to say it will be the most awkward phone call of his political career."