David Cameron has revealed he asked whether the Queen would “raise an eyebrow” about the prospect of Scotland voting for independence from the UK.
The former Prime Minister said he sought the support of royal officials in the days before the 2014 vote, after a prediction that Yes would claim victory “panicked” him.
He later told John Humphrey's on the BBC's Today Programme, he did not ask the Queen for “anything improper”
A poll put the Yes to independence campaign ahead for the first time while he was staying at Balmoral. Mr Cameron told the BBC that the findings felt like a "blow to the solar plexus" and led to a "mounting sense of panic that this could go the wrong way".
He said: "I remember conversations I had with my private secretary and he had with the Queen's private secretary and I had with the Queen's private secretary, not asking for anything that would be in any way improper or unconstitutional, but just a raising of the eyebrow, even, you know, a quarter of an inch, we thought would make a difference."
A few days before the referendum in September 2014, the Queen told a well-wisher in Aberdeenshire that she hoped "people would think very carefully about the future".
The comment was seized on by many pro-union campaigners as an indication that the Queen was urging voters to keep the UK together.
Referring to the Queen's remarks, Mr Cameron said: "It was certainly well covered [by the media] ... Although the words were very limited, I think it helped to put a slightly different perception on things."
Scotland voted to remain in the UK by a 55 per cent to 45 per cent margin.
On Thursday morning, Mr Cameron told Mr Humphreys: “I don’t want to say anything more about this, I’m sure some people would think it may possibly even be that I have already said perhaps a little bit too much.”
He said remarks he made at the time in which he said the Queen had been “purring down the line” to him following the No result had been a “terrible mistake” for which he apologised immediately.
The former PM has also described the "bombshell" moment Mr Gove said he would support the Leave campaign.
Referring to the then-leader Mr Cameron, the Chancellor of the Duchy of Lancaster, Mr Gove, said: "Some of the conversations we had were attempts on his part to reassure himself that our friendship would mean that I wouldn't stray from the fold.
"I think David, understandably, felt that since I'd been prepared to knuckle under on a number of occasions beforehand and put my own feelings to one side in order to serve the team, that on this occasion, that I would do the same."
The first episode of the two part documentary The Cameron Years is broadcast on BBC1 at 9pm on September 19.
