Tory leadership hopeful Jeremy Hunt has refused to commit to taking Britain out of the European Union before Christmas, saying prime ministers should “only make promises they know they can deliver”.

The Foreign Secretary insisted it was possible to get a revised deal with Brussels by the end of September, and said if it took “a few extra days” to get it through Parliament he would delay Brexit beyond the October 31 deadline.

But, when pressed during an interview with the BBC’s Andrew Neil, he refused to say whether the UK would have left by Christmas, though claimed “it’s not going to be months”.

His rival Boris Johnson said it was “absolutely insane” to say that Britain is prepared to delay Brexit again.

Mr Hunt has said that he believes he would be able to get a new deal with Brussels, but if that proved impossible, he would prepare for no deal on October 31, making a judgment on the best course to follow at the end of September.

He expressed his confidence in getting a deal by the end of September, telling the BBC: “I believe we can and I, as I say, I think that people like Angela Merkel want to solve this problem.

“If we have a deal, if it’s clear to us and to the Europeans there’s a deal to be done, then of course I would go for that and if it took a little bit – you know, a few extra days – to get it through Parliament.”

He said Parliament would be “willing to sit at weekends, will be willing to sit late, to do this” but that it “may take a few extra days and I would be willing to allow those days”.

Tory leadership contest timetable (PA Graphics)

Asked whether he would be prepared to delay by days, weeks or months, Mr Hunt replied: “Well it’s not going to be months.”

But pressed on whether the UK would be out by Christmas, he said: “I’m not going to give you those commitments…

“It’s because prime ministers should only make promises they know they can deliver. And there’s another reason why we have to be careful about this 31st of October date.

“It is because Parliament may try and take a no deal Brexit off the table altogether and so I think – my commitment is that I think I’m the best person to get a deal and if we get a deal it will be on or around the 31st of October but I can’t control what Parliament does and that’s why I’m being honest with people about the difficulties.”

Tory leadership race
Boris Johnson being interviewed by Andrew Neil (Jeff Overs/BBC)

Mr Hunt went on to say he expected Brexit to happen before Christmas and, when asked if there was any chance the UK could still go in to 2020 as a member of the EU, he replied: “I don’t believe so, no.”

In a swipe at his Mr Johnson, Mr Hunt said he would deliver Brexit “more quickly than the alternative”.

“If you want to leave the EU quickly, if you want to avoid a general election, which is the risk if you go about this in the wrong way, I’m the person who has the biggest chance of negotiating that deal and getting us out by October 31.”

Mr Johnson, in a separate interview with Neil, repeated his pledge to leave the EU on October 31 “come what may”.

He told the BBC: “I think we’ve got to come out on October 31 and I think it is very odd that those who are saying they would delay even further can’t set another date.

“How much further are we going to wait? We were meant to come out on March 29th. We then were going to come out April 8th. We then delayed it for a further six
months. I think this is leading to a huge erosion of trust in politics.”

Mr Johnson added: “I think it would be absolutely insane now to say that yet again we have a, you know, a phoney deadline, it all can be kicked off until – kick the can down the road ’til the Greek calends.”

He also claimed there was an “outbreak of common sense” beginning to take place within the Tory party and across Parliament – with people “coming together to get this thing done”.

“I don’t think it will be necessary to do anything like proroguing Parliament,” he insisted, but refused to rule it out.

Mr Johnson sidestepped questions about whether he still believed Donald Trump was “stupefyingly ignorant” – in reference to comments he made as London mayor – and came unstuck when grilled on the detail of world trade rules.

Asked how he would handle paragraph 5C of GATT 24, he admitted he did not know what was in it, instead saying: “There’s enough in paragraph 5B to get us the agreement that we want.”

Mr Hunt later conceded he may pay a “political price” for his admission that he may not be able to deliver Brexit by Christmas.

Speaking at a leadership hustings in Cheltenham, he said: “Maybe I will pay a political price for being honest with people.

“But the reality is that we face a hung Parliament with people – not just in the Labour Party but in our own party – absolutely determined to stop us leaving without a deal.”