British Prime Minister David Cameron will apologize to Queen Elizabeth II in person after describing how she "purred" on the telephone when he told her that Scotland had rejected independence, news reports said on Thursday.

Cameron, in the US to attend the United Nations General Assembly, was caught on camera on Tuesday making the remark to former New York Mayor Michael Bloomberg.

"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," Cameron said. "She purred down the line. I've never heard someone so happy."

Cameron's Conservative Party campaigned for Scotland to stay in the UK.

"Look, I'm very embarrassed by this. I'm extremely sorry about it," he told reporters in New York, according to Sky.

Reports said Cameron would apologize to the 88-year-old monarch at her next regular weekly meeting with him.

"It was a private conversation, but clearly a private conversation that I shouldn't have had and won't have again," he told reporters in New York. "My office has already been in touch with the palace to make that clear, and I will do so as well."

By constitutional convention, the queen must remain impartial over political issues such as the Scottish independence debate.

Royal officials had insisted she would not seek to influence last Thursday's closely-fought referendum, but she did tell a well-wisher days before the vote: "I hope people will think very carefully about the future.

"Scotland's First Minister Alex Salmond, who led the campaign for independence, was granted an audience with the queen at her Balmoral residence in the Scottish Highlands on Wednesday, officials said.

Salmond said hours after the referendum result was announced that he would step down in November.

AFP - Reuters