Boris Johnson has “strong views on Brexit … but so do I”, Theresa May has insisted, after resisting calls for the sacking of the foreign secretary in the wake of an explosive leaked recording.

In a private speech to the Conservative Way Forward group, Johnson is heard dismissing the cautious approach of Philip Hammond’s Treasury, which he said had focused on “mumbo jumbo” predictions about short-term disruption, instead of the potential gains from leaving the EU. He also portrayed the Treasury as “the heart of remain”.

May, who was in the air en route to the G7 summit in Canada when the foreign secretary’s words were leaked, was questioned about Johnson’s comments upon landing in Quebec.

“These are complex negotiations. Boris has strong views on Brexit but so do I,” she told Channel 4 News. “I want to deliver for the British people, that’s exactly what we are doing as a government and if you look at the process of these negotiations – nobody ever said it was going to be easy.”

Hammond hit back on Friday, saying he favoured a collaborative rather than confrontational approach. “My experience has been that ... a collaborative approach ... is generally more productive than a confrontational approach,” he said, noting that his advice to his colleagues would be to engage with Britain’s European partners if they wanted a good Brexit deal.

“Finding a mutually beneficial outcome is the only way forward. That is the firm intention of my government. Theresa May, the prime minister, has said so very clearly,” Hammond added.

In the leaked comments, Johnson criticised the significance that the Irish border issue had taken on in the negotiations with Brussels. “It’s so small and there are so few firms that actually use that border regularly, it’s just beyond belief that we’re allowing the tail to wag the dog in this way. We’re allowing the whole of our agenda to be dictated by this folly,” he said.

Earlier, a Downing Street spokeswoman refused to comment directly on the leak, as Labour and the Scottish National party both called on May to sack Johnson over the remarks. However, she rejected the characterisations made in Johnson’s comments. “Northern Ireland has been a priority for the prime minister from day one, and will continue to be so,” she said.

“It is a priority not because the EU has made it one, but because the PM is committed to the union and the emergence of a hard border would put that at risk. I’m not going to engage on the wording, but this is our position and why it is so vital to the PM.”

Asked if the prime minister had full confidence in Johnson, she replied: “Of course ... The PM works with and listens to all her colleagues, and of course there is rigorous debate and you would expect that.” The pair had not spoken, she said, because May had been on her way to the G7 in Canada.

Earlier on Friday, the former Conservative leader Michael Howard said the foreign secretary was right to criticise the Treasury. Howard is, like Johnson, a leading Brexiter, though not an ally of the foreign secretary, whom he once sacked from his shadow cabinet.

Quick guide What Boris Johnson said in leaked recording of speech Show Hide Deep divisions in the cabinet over Brexit have been exposed in a secret recording of a speech Boris Johnson gave to the Conservative Way Forward group. Here are his most contentious comments on ... Donald Trump “Imagine Trump doing Brexit. 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.” Meltdown over Brexit “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 publico, no bloody panic. It’s going to be all right in the end.” The Treasury “The inner struggle is very, very difficult. The Treasury, which is basically the heart of remain, has seized the risk — what they don’t want is friction at the borders. They don’t want any disruption. So they’re sacrificing all the medium and long-term gains amid fear of short-term disruption. Do you see what I’m saying? “And that fear of short-term disruption has become so huge in people’s minds that they’re turning them all wet. Project Fear is really working on them. They’re terrified of this nonsense. It’s all mumbo jumbo.” EU’s orbit “The risk is that it will not be the [Brexit] we want and the risk is that we will end up in a sort of ante-room of the EU, with an orbit around the EU, in a customs union and to a large extent in the single market. So not really having full freedom on our trade policy, our tariffs schedules, and not having freedom with our regulatory framework either, in the lunar pull of the EU. “What they are trying to do is do a Brexit that does as little change as possible and that keeps us basically in the same orbital pull … and that would be the worst of both worlds.” Photograph: Toby Melville/X90004

“That fear of short-term disruption has become so huge in people’s minds that it’s turning them all wet,” Johnson said. “Project Fear is really working on them.”



Speaking to BBC Radio 4’s Today programme, Howard said: “If there are people in the Treasury who are doing that, then they shouldn’t be, and I deplore that.”



He also played down the divisions in the cabinet that the secret recording exposed as the “spills and thrills” of the Brexit negotiations.

Howard claimed Johnson was joking when he spoke approvingly of a imaginary scenario in which Donald Trump was leading the Brexit talks.

Johnson was recorded 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.”

Leaked comments by Boris Johnson expose cabinet divisions Read more

Johnson said he had become “increasingly admiring of Donald Trump” and had become “convinced that there is method in his madness”.

Asked about the Trump comments, Howard said: “That is a thought I would prefer not to entertain. I suspect he had his tongue in his cheek when he said it.”

In his speech, Johnson urged Tory donors not to panic during a probable “meltdown” over Brexit. Howard said: “He is certainly right to say we shouldn’t panic. I don’t know about a meltdown I’m not as close to the negotiations as Boris is. But there always going to be thrills and spills and what we have to do is to focus on the essentials of the situation.”

The Tory grandee attacked remainers on the Conservative backbenches for trying to “nudge” the prime minister into staying in the customs union.

Facebook Twitter Pinterest Michael Howard: ‘If there are people in the Treasury who are doing that, then they shouldn’t be.’ Photograph: Sky News

He said: “She is not going to be nudged through the back door. She is going to stick to what she has said, which is that we will leave the customs union and we leave the single market and we have to do that to capture the advantages of Brexit.”

The shadow foreign secretary, Emily Thornberry, repeated a call she first made last November for her opposite number to be dismissed.

Emily Thornberry (@EmilyThornberry) As I was saying to Boris Johnson in November... pic.twitter.com/qFL1KWe6ru

Earlier, Scotland’s first minister, Nicola Sturgeon, also called for Johnson to go. Speaking to BBC News, she said: “Any prime minister that had any semblance of authority would have got rid of Boris Johnson a long time ago, not just because of comments like this ... I just don’t think Boris Johnson is somebody who should be in one of the high offices of state.”