Boris Johnson has been recorded praising Donald Trump and suggesting the US president’s aggressive approach might achieve more in Brexit talks than the UK government is currently doing.

The British foreign secretary warned that negotiations with Brussels were heading towards “meltdown”, saying Brexit supporters risked getting a far worse deal than they had expected.

His comments came on Wednesday night at a private dinner of Conservative supporters in London, and have been reported by BuzzFeed News which obtained an audio recording.

Johnson appeared to accuse the government of heading towards a so-called “soft” Brexit whereby the UK would cling to existing ties with the European Union. He said the government was so terrified of short-term disruption that it risked throwing away opportunities a more independent stance would bring.

‘Imagine Trump doing Brexit’

The foreign secretary said he had become “increasingly admiring of Donald Trump”, adding that he had “become more and more convinced that there is method in his madness”.

“Imagine Trump doing Brexit,” BuzzFeed quoted Johnson as saying. “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”.

He attacked the UK Treasury (finance ministry) as being “the heart of Remain”, describing as “nonsense” and “mumbo jumbo” its fears of “friction at the borders” and “short-term disruption”.

Johnson dismissed warnings of chaos because of delays at borders, saying disruption would be “bumps in the road”.

Treasury analysis has said disruption at Dover could lead to food and medicine shortages if there is no Brexit deal with Brussels. The foreign secretary said another warning by the head of the UK’s customs service, over the alleged multi-billion pound cost of one government proposal, was “out by a factor of 10 or 20”.

He also said warnings about the impact of a hard border between Northern Ireland and the Irish Republic had been overblown, describing them as “pure millennium bug stuff” – a reference to unfounded fears that the turn of the century would bring widespread computer meltdown.

May feels Cabinet squeeze

Boris Johnson’s comments – made at the Institute of Directors to members of a Thatcherite campaign group called Conservative Way Forward – came as pressure was already mounting on Prime Minister Theresa May from within her own Cabinet over Brexit.

The Brexit minister David Davis reportedly threatened to resign over the so-called “backstop” solution for Northern Ireland, to guarantee an open border after the UK leaves the EU.

The government has since published a plan imposing a time limit on a proposal whereby the UK would temporarily match EU tariffs, in the face of Brexiteer fears that such an arrangement might continue indefinitely.

The European Union has called for more clarity from the UK on its trade objectives, ahead of a key summit in Brussels later this month. The UK is set to leave the EU in March 2019.

The British government has been paralysed by internal divisions over the country’s future relationship with the EU after Brexit.

Boris Johnson said he thought the prime minister would soon become “much more combative with Brussels”, according to BuzzFeed.

“You’ve got to face the fact there may now be a meltdown. OK? I don’t want anybody to panic during the meltdown. No panic. Pro bono public, no bloody panic. It’s going to be all right in the end.”