In his latest indiscreet remarks likely to embarrass Prime Minister Theresa May, Johnson said the government was reaching a phase in negotiations “where we are much more combative with Brussels”.

“You’ve got to face the fact there may now be a meltdown. OK?” he told Conservative activists earlier this week, according to a secret recording leaked to BuzzFeed News.

“I don’t want anybody to panic during the meltdown. No panic. Pro bono publico, no bloody panic. It’s going to be all right in the end.”

He added, according to further quotes revealed in The Times: “Take the fight to the enemy — absolutely right. We need to — and we will.”

Johnson, Britain’s chief diplomat, also said he was “increasingly admiring of Donald Trump.

“I have become more and more convinced that there is method in his madness”.

“Imagine Trump doing Brexit,” he said.

“He’d go in bloody hard… There’d be all sorts of breakdowns, all sorts of chaos. Everyone would think he’d gone mad. But actually you might get somewhere. It’s a very, very good thought.”

The leading Brexiteer talked about divisions within the British government, saying that Brexit “will happen, and I think it will be irreversible, but… the risk is that it will not be the one we want”.

He said the establishment was seeking to ensure that Brexit “does as little change as possible”, with “the risk is that you will end up in an anteroom of the EU, locked in orbit around the EU”.

Away from domestic politics, Johnson also suggested May would put forward a new plan at the G7 summit in Canada for a “rapid response unit” to deal with Russian aggression, including cyber-warfare.

On China, he said: “We need to engage with China diplomatically, treat China as our friend and our partner, but also recognise that they are our commercial rivals. And they will try to stiff us.”

Johnson also said US Secretary of State Mike Pompeo had asked Britain to use its nuclear expertise in helping North Korea dismantle its arsenal.

“What they want us to do is to use our nuclear expertise to dismantle Kim Jong-Un’s nuclear missile. That’s what he asked me to do today,” he said. DM