Boris Johnson insisted he loved and admired the NHS, dismissing Labour’s fears that he would sell it off to the Americans in a post-Brexit trade deal as “pure Bermuda Triangle stuff”.

As the two leaders clashed on a range of topics in their last TV debate, some of the most passionate exchanges came when they locked horns on what polls suggest people put at the top of their agenda during the election campaign: health care.

Jeremy Corbyn insisted the NHS was at “breaking point, at crisis point” as he clashed with the Prime Minister on nurse numbers and hospital figures and again raised the spectre of a future Tory Government selling off parts of the health service to US business.

Gesticulating, Mr Johnson talked about building 40 new hospitals and dismissed the Labour leader’s claims, declaring: “This is pure Bermuda Triangle stuff. We've heard it time and time again from the Labour Party during this election campaign. We'll be hearing about 'little green men' next.

“I use the NHS. I love it. It’s one of the most important things about this country…It’s a fantastic thing. Under no circumstances will we sell it off to anybody in any kind of trade deal.”

Elsewhere in the debate, the two leaders also engaged in angry exchanges over racism and anti-Semitism.

The PM accused Mr Corbyn of a "failure of leadership" in his handling of anti-Semitism in the Labour Party. But the Labour leader shot back that he never used racist language and that he hoped Mr Johnson regretted his past comments.

Mr Johnson said it was "extraordinary" the Chief Rabbi had felt the need to speak out during an election campaign about his fears for his community if Mr Corbyn became PM.

The Labour leader insisted there was "no place" in his party for anti-Semitism, adding in an apparent reference to Mr Johnson's past comments: "I do not ever use racist language in any form to describe anybody in this world or in our society."

Mr Johnson replied: "Mr Corbyn I am sure is very well-intentioned but in his handling of this particular issue, his unwillingness to take a stand to stand up for Jewish people in the Labour Party, his unwillingness to protect them, to put an arm round them, is in my view a failure of leadership."

Mr Corbyn retorted: "The failure of leadership is when you use racist remarks to describe people in different countries or in our society. I will never do that and my will never do that.

"I hope the Prime Minister understands the hurt that people feel when they hear remarks and articles that he has written in the past. I hope that he will regret those," he added.

Elsewhere, Sir John Major made an extraordinary intervention, effectively urging people not to vote Conservative in three constituencies but, rather, opt for pro-Remain Independent candidates.

Speaking at a rally in London, which called for a second EU referendum, the former Tory Prime Minister said, if he lived in their constituencies, he would vote for ex-ministers David Gauke, Dominic Grieve and Anne Milton; all of whom lost the party whip earlier this year after rebelling against Mr Johnson on Brexit.

"Let me make one thing absolutely clear: none of them has left the Conservative Party, the Conservative Party has left them,” declared Sir John.

"Without such talent on its benches, Parliament will be the poorer, which is why - if I were resident in any one of their constituencies - they would have my vote."

The former premier described Brexit as the "worst foreign policy decision in my lifetime" and warned leaving the EU would affect "nearly every single aspect of our lives for many decades to come".

"It will make our country poorer and weaker. It will hurt most those who have least. Never have the stakes been higher, especially for the young. Brexit may even break up our historic United Kingdom," added the former Tory leader.

Tony Blair, who also spoke at the rally, argued that a Conservative Party which expelled the likes of Michael Heseltine and disowned the statesmanship of Sir John did “not deserve to govern unchecked and the country would not be wise to let them”.

He added: "It's not Brexit that's getting done. We're getting done. This is the final chance for a final say. It's not one General Election but 650 individual ones. Think long. Think hard. Time to choose. Choose wisely."

Earlier, Jeremy Corbyn called a press conference to reveal a confidential Treasury document, which, he insisted, showed that Mr Johnson had been caught “red-handed” misleading the public in his insistence that there would not be a customs border down the Irish Sea.

"It is there in black and white,” declared the Labour leader. “It says there will be customs declarations, absolutely clearly, for trade going from Northern Ireland to Great Britain.”

But the PM hit back, insisting Mr Corbyn’s charge was "complete nonsense" and that the whole of the UK would leave the EU “whole and entire”.

The Democratic Unionists’ Sir Jeffrey Donaldson said the leaked document was a “further demonstration that the PM’s deal would be bad for Northern Ireland”.

Mr Johnson, meanwhile, made clear he would not succumb to the pressure for him to submit himself to an interview with the BBC’s forensic interrogator Andrew Neil.

Tory high command suggested: “The public are fed up with interviews that are all about the interviewer and endless interruptions. The format is broken and needs to change if it is to start engaging and informing the public again.”

On the stump in Kent, the PM said he had done 118 sit-down interviews during the campaign and joked: “There's a guy called Lord Buckethead who wants to have a head-to-head debate with me. Unfortunately, I'm not able to fit him in. You know, we can't do absolutely everything."

But the Lib Dems said Mr Johnson had “bottled it”. Sir Ed Davey, their deputy leader, claimed: “The public will rightly see Boris Johnson as the coward he is for failing to be held accountable in the same way as the other party leaders.”

In other developments:

*Mr Johnson announced a Conservative majority Government would invest £550 million into grassroots football as the centre of its plans to back a UK/Ireland World Cup 2030 bid.

Insisting he would put his “heart and soul behind the case for a UK and Ireland World Cup in 2030,” the PM said he wanted the tournament to be about more than just football, “I want it to transform lives with a legacy to match the 2012 Olympics”.

*The Electoral Commission has been urgently called in by The People’s Vote campaign to look into the possible non-disclosure of up to £500,000 in donations under the organisation’s previous management.

*Channel 4 News was accused by Tory high command of “inventing” a quote after it apologised for erroneously producing a social media clip which reported Mr Johnson saying he was in favour of having "people of colour" come to the UK; he actually referred to "people of talent".

*Conservative HQ suggested Labour’s plans for a new “land value tax” would clobber high streets and town centres by as much as £5 billion a year.

*BBC News, ITV News and Sky News announced plans to release a joint election exit poll when ballots close at 10pm next Thursday.

*The Lib Dems said their analysis showed almost one million businesses had closed in past three years amid Brexit uncertainty and today, to mark Small Business Saturday, the party highlighted its plan to scrap business rates and replace them with new land value tax on landlords.

*Tory HQ pulled a visit by the PM to Rochester for "logistical reasons" after protesters turned up at Ye Arrow pub with signs "Austerity killed over 130,000, blood is on your hands" and "No to racism, no to Boris Johnson".

*Mr Corbyn proclaimed the benefits of Marmite despite its divisive nature among consumers after being asked whether Labour would fare better among working-class voters without himself at helm.