David Cameron: 'Every day I think of the Brexit referendum and the fact that we lost'
Cameron still has trouble sleeping at night after Brexit defeat
He was so confident about securing the EU referendum for Remain that he boasted to fellow European leaders that he was a "lucky" prime minister who knew "how to win".
Instead, the shock of losing the vote, and his job as prime minister, caused David Cameron to become "hugely depressed", he has disclosed, in a fascinating account of how and why he inadvertently set Britain on course for Brexit.
Having gambled everything - and lost - on his conviction that the UK would choose to stay in the EU, Mr Cameron admits he has trouble sleeping at night, but insists the referendum was "inevitable".
"I think about this every day," he said in an interview with 'The Times' to publicise his memoir, 'For The Record'.
"Every single day I think about it, the referendum and the fact that we lost and the consequences and the things that could have been done differently, and I worry desperately about what is going to happen next."
Although the majority of voters backed Brexit, Mr Cameron believes it is a backward step, and he is tormented by the consequences of the events he set in motion, to the extent that it has affected his health.
He was "hugely depressed about it" when the Leave campaign, headed by Boris Johnson and Michael Gove, emerged victorious.
Asked if he was clinically depressed, he replied that he was not "on medication".
He is often shouted at in the street, saying: "People come up and say all sorts of things. I've had some robust exchanges... I totally recognise the uncertainty has been painful and difficult. It's been difficult for all sorts of people in all sorts of walks of life." Asked whether he has trouble sleeping, he said: "I worry about it a lot."
Despite losing the referendum after campaigning for Remain, despite losing his job, and despite the current Brexit crisis facing Mr Johnson, Mr Cameron has no time for regrets, as he says he could not have done anything differently even if he had the ability to turn back the clock.
"As I say, when I think through all the things I thought and all the arguments I had with colleagues and myself, I still come to the same conclusion: that we were going to have a referendum."
He acknowledges that "some people will never forgive me for holding a referendum. Others for holding it and losing it", but adds: "There are, of course, all those people who wanted a referendum and wanted to leave who are glad that a promise was made and a promise was kept."
He said he had tried to explain in his book "why I felt this was inevitable".
He says: "This issue needed to be addressed and I thought a referendum was coming, so better to try to get some reforms we needed and have a referendum. But I accept that, you know, that effort failed. I do understand some people are very angry because they didn't want to leave the EU. Neither did I."
The decision caused huge rifts with his closest friends and colleagues that have never healed - his loyal chancellor George Osborne still refers to "you and your f***ing referendum", and he has barely spoken to Mr Gove or Mr Johnson since.
Addressing whether he feels guilt over his decision to call a referendum he explains it was not something he took lightly.
"I get very frustrated when I read - which I do frequently - that a referendum was held because of the results of the 2014 European election [when Ukip emerged as a genuine threat to the Tories]. It's simply not true. The referendum was announced a year beforehand and I thought about it more than any other decision I took... but it seemed to me there was a genuine problem between Britain and the EU with the eurozone crisis and the development of the euro that needed fixing.
"There was also - I don't deny it for a second - a huge political pressure to have a referendum, partly because we'd had treaty after treaty and promise after promise, and this issue was not going to go away."
Mr Cameron traces the origins of the referendum back to 2011, when Britain vetoed a change to the EU treaty designed to help solve a crisis in the eurozone.
Instead of respecting Britain's right of veto, the EU carried on regardless without the UK in the discussions.
Mr Cameron tried to avoid the need for a referendum by trying to recast Britain's relationship with the EU, but his efforts fell flat.
He said he needed the threat of a referendum to have any chance of success in negotiating with Brussels because "politicians couldn't keep saying 'we'll have a referendum at some stage but not now'," but he accepts that "one of my biggest mistakes" was allowing expectations of what was possible to "get far too high".
As a result, his new deal - which exempted Britain from the EU's "ever closer union" mantra and limited benefit payments to EU migrants - was "dumped" on.
Having failed to win backing for his tweaked arrangement with the EU, Mr Cameron had no choice but to call the referendum he had promised.
He was guilty of hubris before the vote, telling European politicians, "I am a lucky man, I know how to win," according to one Czech former minister, forcing him to make humiliating apologies to world leaders when Britain voted to leave.
The morning after the referendum he rang US President Barack Obama and leaders of the 27 other EU countries to tell them: "I am sorry." With the benefit of hindsight, he now acknowledges he misjudged the mood of the Tory party and the country, saying: "Something I got wrong was that the latent Leaver gene in the Conservatives was much stronger [than I thought]. There were lots of people - councillors, Conservative members, Conservative newspapers, friends - who, as far as I knew, had never expressed the view of wanting to leave the EU and then suddenly decided they absolutely did want to. I didn't foresee that."
He also accepts that Dominic Cummings, the Vote Leave campaign guru who is now Boris Johnson's senior strategist in Number 10, managed to reach people who had never voted before, confounding the polls that had consistently said Remain would win. "It's true the reason, or one of the reasons, the opinion polls got it wrong was that... this time non-voters voted," he said.
Explaining why the Remain campaign failed, he says: "In the end we ended up with very strong technical and economic arguments and the opposition had a powerful emotional argument.
"I think the issue of immigration plus that emotional argument was a winning combination for them. The argument about control, it resonated with people, and when you asked them 'well, what is it that we're going to control?', it was this issue of immigration."
He said he tried to make the argument that the EU had helped to bring together countries that had previously fought each other in wars, but "it just didn't work" and as the referendum campaign wore on "I just felt more and more bogged down".
"It turned into this terrible Tory psychodrama and I couldn't seem to get through. What Boris and Michael Gove were doing was more exciting than the issues I was trying to get across," he says.
"I felt like I was in a sort of quagmire by the end."
For him, the referendum campaign is remembered as much for personal betrayal as personal failure.
Mr Gove, in particular, was one of his closest friends before the campaign; their children went to the same school. Mr Gove promised he would not play a leading role in the Leave campaign, only to break his word, and their friendship.
In contrast to his sense of betrayal at Mr Gove, he believes Mr Johnson's decision to back the Leave campaign, was more about personal ambition. "I think he was genuinely torn."
Mr Cameron claims that "Boris thought he was going to lose" in the referendum and that he said "Brexit will be crushed", but believed that he had a better chance of eventually being chosen as Tory leader if he showed his Eurosceptic credentials.
To try to persuade him to back Remain, Mr Cameron offered him a "top five" cabinet job, such as defence secretary, but Mr Johnson declined. (© Daily Telegraph, London)