British Prime Minister David Cameron on Sunday apologized for revealing details of Queen Elizabeth's relief that Scotland had voted to keep the United Kingdom intact, saying he was kicking himself very hard for the breach of protocol.

Cameron was last week caught on a live microphone telling former New York mayor Michael Bloombergthat the Queen had "purred down the line" to him when he spoke to her following the results of the Sept. 18 referendum, in which Scots voted to reject independence.

"It's one of those moments where you look back and kick yourself very hard," Cameron said on BBC television.

"It was not a conversation I should have had, even though it was a private conversation and I'm extremely sorry and very embarrassed about it. I've made my apologies and I think I'll probably be making some more."