David Cameron has accused Boris Johnson and Michael Gove of leaving "the truth at home" over Brexit as he said they behaved “appallingly” during the EU referendum campaign.

In an excoriating attack by an ex-prime minister on one of his successors, Mr Cameron criticised his former friends and colleagues over the claims they made about £350m a week payments to Brussels on their campaign bus.

Casting doubt on Mr Johnson’s promise of getting Britain out of the EU on Oct 31 with or without a deal, Mr Cameron also suggests a second referendum might now be necessary, saying: “I don’t think you can rule it out because we’re stuck.”

In his long-awaited memoir, which is published next week, and in an interview with The Times newspaper, Mr Cameron says of the referendum: "I deeply regret the outcome and accept that my approach failed. The decisions I took contributed to that failure. I failed."

The outcome, which led to his resignation, left him "hugely depressed", while he also opens up about his drug-taking past and about the highs and lows of his coalition with the Liberal Democrats.

He accuses Mr Johnson of "sharp practices" in proroguing Parliament and savages his decision to expel rebel Tories, as well as calling Mr Gove “mendacious” and even refers to the Cabinet minister as a “w****r”.