LONDON — Former prime minister David Cameron has broken his long silence on Brexit, confessing in new memoirs that he is “truly sorry” for the chaos and rancor that has engulfed Britain after it voted to leave the European Union three years ago.

“I failed,” Cameron concedes in his book, “For the Record,” excerpted on Saturday in the London Times.

The memoirs are artfully revealing. Cameron both covers his posterior and concedes some mistakes — of strategy and timing, mostly. He admits he is today “depressed” about Brexit; he charges that the current prime minister, Boris Johnson, was a major misleader; and he confesses he smoked a lot of dope during his Eton school days — sneaking off to an island in the River Thames to get “off my head” on marijuana.

It was Cameron who confidently called for the June 2016 Brexit referendum — and it was Cameron who led the muddled, muted campaign for Britain to remain in the European Union.

After Brexit won 52 percent to 48 percent, Cameron quickly resigned, notably caught on a hot mic humming a tune as he strode away from the podium in front of 10 Downing Street.

Many Britons blame Cameron for today’s Brexit quagmire, branding the former prime minister as “the man who broke Britain.”

Cameron’s critics say the British public was never really clamoring for the 2016 referendum and that Cameron called it only to quell internal squabbles in his fractious Conservative Party and to quiet the rabid Tory tabloids.

Cameron confesses the whole thing quickly devolved into a “terrible Tory psychodrama.”

In an interview with the Times newspaper, as a part of the book’s pre-publication publicity campaign, Cameron labeled Prime Minister Johnson’s possible “no-deal” Brexit “a bad outcome.” 

He also warned that the country might be forced to stage a second referendum on whether to leave the European Union.

“I don’t think you can rule it out, because we’re stuck,” said Cameron, who served as prime minister from 2010 to 2016.

In his memoir and interview, Cameron charges that his former political chums — Johnson and his sidekick, the current government minister in charge of carrying out Brexit, Michael Gove — misled voters in 2016 about the swell benefits of leaving Europe.

Cameron calls his former friend Gove “mendacious” and says Gove and Johnson behaved “appallingly” during the 2016 referendum.

Cameron points to their false pro-Brexit claims that Turkey was about to join the European Union (it wasn’t) and their suggestions that soon Britain would be flooded by millions of Turkish Muslim immigrants (never happened).

Although he does not call Johnson or Gove liars, Cameron said the pair “left the truth at home” when they claimed, for example, that leaving Europe would produce a $440 million a week windfall to fund the country’s beloved National Health Service.

“Boris had never argued for leaving the EU, right? Michael was a very strong Eurosceptic, but someone whom I’d known as this liberal, compassionate, rational Conservative ended up making arguments about Turkey and being swamped and what have you. They were trashing the government of which they were a part, effectively,” Cameron told the newspaper.

In a bit of a side-dish, Cameron remembers Johnson’s current special adviser, Dominic Cummings, who ran the leave campaign in 2016 and came up with the slogan “take back control,” for spreading “poison” and turning Tory against Tory.

Cameron said his Brexit defeat three years ago has left him “hugely depressed.”

“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,” Cameron said.

And yet. The former leader still argues that Britain was never really comfortable in the European Union and that a referendum was “inevitable” and the “right approach.”

Essentially, Cameron wants it both ways. He failed. But it was the right thing to do.

In his interview, Cameron criticizes Johnson’s move recently to suspend Parliament and accuses him of “sharp practices” in stripping 21 Conservative lawmakers of their party membership for rebelling against him.

In other excerpts, Cameron recalls with some shame his membership in the elite University of Oxford drinking society, the Bullingdon Club. At his initiation into the posh ranks, he remembers how he awoke hung over, with wine bottles piled outside his door, to find a group of his new Bullingdon buddies — which probably included Boris Johnson, Cameron admits he cannot quite recall — “with one of them standing on the legs of an upended table, using a golf club to smash bottles as they were thrown at him.”

It is a stunning image of the two men who would come to define the Brexit age.