Jeremy Hunt has issued a warning to Boris Johnson that failure to swing behind Theresa May risks opening the door to a Labour government, which he claimed could stop Brexit in its tracks.

The health secretary made the comments after being asked if he feared the foreign secretary was “looking at the top job”.

“What do you think?” replied Hunt, laughing, before adding: “All I would say to anyone who might be eyeing a different job is that Jeremy Corbyn is also eyeing a different job.

“And if they don’t swing behind Theresa, who I think is doing a fantastic job in very difficult circumstances, they will just open the door to Jeremy Corbyn and probably the most dangerous leftwing government this country has ever seen.”

The interview with the Guardian came after a series of interventions by Johnson that have dominated the news agenda, including a newspaper interview that was seen to be laying down red lines on the government’s EU negotiations.

Hunt said he had “very grave doubts” that Corbyn would deliver Brexit if he was elected because of disagreements within Labour about free movement and the single market.

“Every Conservative cabinet minister needs to recognise that if they don’t pull in behind Theresa May then they are risking Brexit,” he said, in comments that will be seen as aimed at Johnson.

Hunt said he was 100% behind the prime minister, including for the next general election. “I would be right behind her to lead us into the next election. She is doing a fantastic job in challenging circumstances,” he said.

The health secretary warned that the NHS would “fall down” without 150,000 EU citizens working in hospitals and communities across the country, saying he would use his conference speech on Tuesday to try to offer people reassurances.

Asked if the NHS was properly staffed – amid warnings of a crisis and the recent revelation that two junior doctors were left in charge of 436 patients at Derriford hospital in Plymouth – Hunt said it was not. 

“No, we’ve got to do a lot better,” he said. ”Workforce planning has been woeful for a very, very long period of time.” 

He said that health secretaries, including himself, had been too short-termist in their approach to the NHS, as he revealed his centrepiece announcement for a 25% increase in nurse training places from next year. Hunt said the rise was the biggest in the history of the NHS and there would also be more places available through the apprenticeship route. 

His comments in response to questions about the foreign secretary came as:

• Conservative members flocked to events attended by Jacob Rees-Mogg, the maverick Eurosceptic backbencher who has been tipped as a potential leadership candidate. With a strongly pro-Brexit mood among delegates, the audience at one fringe shouted “no” when Tory MPs were asked if Johnson should resign.
• Andrea Leadsom, the leader of the Commons, appeared to align herself with Johnson, who she described as fantastic. She said both served in the cabinet at May’s discretion and argued that the UK would take back control of all laws and its money from March 2019, in contradiction of the prime minister’s Florence speech.
• Philip Lee, a junior justice minister and former GP, sparked outrage after claiming the NHS was “a Ponzi scheme that’s about to collapse”, earning a rebuke from Hunt.
• There were reports that David Davis had said he would step down as Brexit secretary after Britain formally leaves the EU, and that Amber Rudd was considering using the polling company of Lynton Crosby to help with her campaign to keep her seat at the next election.

Johnson himself won support from grassroots members and allies who believe he is simply ensuring that the Brexit vote is delivered. But his actions have appeared to frustrate a number of cabinet colleagues and other senior figures.
The chancellor, Philip Hammond, said that no one was denying different views on Brexit in the cabinet and said Johnson had been making arguments people knew he believed.

But asked on Sky News if the foreign secretary should shut up, he replied: “I think the more we can show unity, the stronger our negotiating position with the European Union would be.”

The Tory Scottish leader, Ruth Davidson, also had a dig at the foreign secretary, saying: “I have a lot of MSPs at this conference – if any of you think about writing anything without telling me that runs counter to Conservative policy, you’re out on your ear because nobody is unsackable.”

Privately, other figures also expressed their frustration. One cabinet member told the Guardian: “Please don’t mention the B word”; another said that the interventions were damaging, but little could be achieved by forcing Johnson out. 

Speaking about health, Hunt admitted that staffing was a significant issue as he reached out to EU citizens not to leave the UK.

“We want them to stay and we’re confident they will be able to stay with broadly the same rights as now,” he said, adding that the European workers were hugely valued and needed in an uncertain time. “We certainly can’t afford to lose them.”

He argued that more could be done on the issue of pay outside the basic salary, with plans to pilot a new app through which health workers could take on additional hours at short notice. Affordable homes built on NHS land would have to be first offered to health workers, he said.

Admitting that the NHS was not properly staffed, amid warnings of serious strains, Hunt explained what he believed had been a key part of the problem.

“It has been a mistake made by successive health secretaries in all parties, that when you’re faced with a choice: do you put money into training more doctors and nurses [who] won’t come out of training in a nurse’s case for three or four years, or a doctor’s case six or seven years – or do you put the money into more cancer treatment today?

“Inevitably people take the decision to spend it on immediate priorities, even if it is not the right thing for the long term of the NHS.”
Hunt admitted that the party had to act on widespread concerns about public sector pay, many of which were raised during the election campaign, including by lifting the pay cap. But he admitted that could mean a challenge elsewhere for the NHS budget.

Hunt said properly resourced staffing was the priority for the health service but, asked where the money would come from, he said: “There is a big discussion to be had about that.”

He said the Tories’ biggest challenge was to take on Labour’s arguments, saying his party was ready to improve funding to the NHS and that services were improving despite challenging demographics.

“The biggest danger to the NHS right now is Jeremy Corbyn’s economic policies, because if you crash the economy, then where is the money going to come from that we need to fund all those doctors and nurses?”

Asked how many cabinet members wanted to be prime minister, he replied: “Oh I think probably everyone in the cabinet has a little corner of their heart – probably every member of parliament has a little corner of their heart – they think they’d like to have a crack at the top job.”

He admitted that in the past he had said he would love to be prime minister, but was now focused on the health job, which he believed was the most important in cabinet.

“What I’m passionate about is making the NHS the safest and best healthcare service in the world, and if that is written on my grave I’d be very happy.” 

A spokesman for Johnson said: “Boris is 100% behind the Florence speech and the words red line have never passed his lips. He wrote an article two weeks ago that was in line with government policy and hasn’t deviated from it.”

Source: Guardian