Boris Johnson has admitted his TV comments on Kim Darroch were “a factor in his resignation” – but insisted the former US ambassador was given a false account.

The favourite in the race for No 10 insisted Sir Kim had not – as widely reported – watched the programme, but merely been told that Mr Johnson had failed to back him.

However, revealing a conversation between the pair, Mr Johnson said: “He said that what somebody had relayed to him had certainly been a factor in his resignation.”

But, being grilled by the BBC’s Andrew Neil, he added: “I think that, unfortunately, what I said on that TV debate was misrepresented to Kim.”

Until now, Mr Johnson has insisted the resignation was not connected to his TV appearance – dismissing protests, including from Tory MPs, that the diplomat had been “thrown under a bus”.

Sir Kim quit after his savaging by Donald Trump and within hours of the Tory leadership favourite refusing, repeatedly, to say he would keep the ambassador in his post.

Biggest lies told by Boris Johnson Show all 5 1 /5 Biggest lies told by Boris Johnson Biggest lies told by Boris Johnson Made-up quote for The Times Johnson was sacked from The Times newspaper in the late 1980s after he fabricated a quote from his godfather, the historian Colin Lucas, for a front-page article about the discovery of Edward II’s Rose Palace. “The trouble was that somewhere in my copy I managed to attribute to Colin the view that Edward II and Piers Gaveston would have been cavorting together in the Rose Palace,” he claimed. Alas, Gaveston was executed 13 years before the palace was built. “It was very nasty,” Mr Johnson added, before attempting to downplay it as nothing more than a schoolboy blunder. PA Biggest lies told by Boris Johnson Sacked from cabinet over cheating lie Michael Howard gave Boris Johnson two new jobs after becoming leader of the Conservatives in 2003 – party vice-chairman and shadow arts minister. He was sacked from both positions in November 2004 after assuring Mr Howard that tabloid reports of his affair with Spectator columnist Petronella Wyatt were false and an “inverted pyramid of piffle”. When the story was found to be true, he refused to resign. PA Biggest lies told by Boris Johnson Broken promise to boss In 1999 Johnson was offered editorship of The Spectator by owner Conrad Black on the condition that he would not stand as an MP while in the post. In 2001 he stood - and was elected - MP for Henley, though Black did allow him to continue as editor despite calling "ineffably duplicitous" PA Biggest lies told by Boris Johnson Misrepresenting the people of Liverpool As editor of The Spectator, he was forced to apologise for an article in the magazine which blamed drunken Liverpool fans for the 1989 Hillsborough disaster and suggested that the people of the city were wallowing in their victim status. “Anyone, journalist or politician, should say sorry to the people of Liverpool – as I do – for misrepresenting what happened at Hillsborough,” he said. PA Biggest lies told by Boris Johnson ‘I didn’t say anything about Turkey’ Johnson claimed in January, that he did not mention Turkey during the EU referendum campaign. In fact, he co-signed a letter stating that “the only way to avoid having common borders with Turkey is to vote Leave and take back control”. The Vote Leave campaign also produced a poster reading: “Turkey (population 76 million) is joining the EU”

Alan Duncan. a junior foreign office minister, described his behaviour as “contemptible”, but Mr Johnson had called the allegation of a connection “bizarre”.

In his interview with Mr Neil, Jeremy Hunt, the underdog in the race, refused to say the UK would leave the EU “by Christmas” – despite Mr Johnson’s vow to be out by 31 October.

“I’m not going to give you those commitments,” the foreign secretary replied, arguing MPs could yet thwart any attempt to carry out a no-deal Brexit on Halloween.

Pressed again on if Brexit would happen “before Christmas”, Mr Hunt replied: “I would expect so, yes,” – before leaving open the possibility of membership continuing into 2020.

He underlined his slim chances of success, by admitting his “worry” was that Conservative members would “vote with their hearts instead of their heads”.

However, fewer than half of Tory members have returned their leadership ballots, ahead of the end of the race on 22 June, according to an internal update given this week.

Turnout is said to be between 45 per cent and 50 per cent – a much lower figure than claims, by Mr Johnson’s supporters, that at least two thirds of the 160,000-strong membership had voted already.

In his interview, Mr Johnson faced the accusation that he would be “craven” to Mr Trump, given their friendship and the way he sided with the US president over the Darroch affair.

He called the suggestion “ridiculous”, arguing he had stood up to Mr Trump when he “saw fit to insult London”, in his time as the capital’s mayor.

But Mr Johnson refused, five times, to repeat his 2015 criticism that Mr Trump was “stupefyingly ignorant” over his call for a ban on Muslims entering the US.

“You’re not going to answer, are you,” Mr Neil said, having suggested that “people worry will you be as craven if you were prime minister”.

Mr Johnson said he did not want to prorogue – or suspend – parliament to ram through a no-deal Brexit through, but, again, he would not rule it out.

The exchanges were criticised by Ian Murray, a Labour supporter of the People’s Vote campaign, who said: “This has been the week where we have been able to peer into what the future would be if Brexit is delivered by a prime minister Boris Johnson.

“His refusal to stand up for our impartial civil servants shows he would be craven in the face of a bullying Donald Trump.”

Mr Neil also took Mr Johnson to task over his claims Article 22 of the General Agreement on Tariffs and Trade (GATT) would allow the UK to continue to trade with the EU tariff-free for up to 10 years in the event of a no-deal Brexit.