THERESA May will underline the Tories’ attempts to turn the General Election into a presidential campaign by insisting the June 8 vote is about putting either herself in Number 10 or Jeremy Corbyn.

Visiting another traditional Labour seat, she will tell a campaign event in Leeds this evening: “It may say Labour on the ballot but it’s Jeremy Corbyn that gets the vote.”

Her remarks follow the personal attack on the Labour leader by Boris Johnson, the Foreign Secretary, who branded him a “mutton-headed old mugwump,” who would be a threat to national security.

Mr Corbyn pledged to avoid "name-calling" while his colleague John Healy, the Shadow Housing Minister, claimed Mr Johnson had demeaned the office of Foreign Secretary and said: “This is Boris Johnson feeling left out of the election campaign,” noting how the incident was a case of “look-at-me name-calling that you’d see in the Eton playground”.

In her campaign speech, the Prime Minister will make a direct appeal to Labour voters.

She is expected to say: “I know this city is one of the places that people call a ‘traditional Labour area’ but here – and in every constituency across the country – it may say Labour on the ballot but it’s Jeremy Corbyn that gets the vote.

“There are only two people who can possibly be Prime Minister on June 9; only two people who can possibly represent Britain in Europe. The choice is between five years of strong and stable leadership with me as Prime Minister or a coalition of chaos with Jeremy Corbyn at the helm, a weak leader negotiating Brexit and higher taxes, debt and waste.”

She will go on to say: “That is why in this election – the most important election this country has faced in my lifetime – every single vote counts and everyone in our country has a positive reason to lend me their vote. Because this election is not about who you may have voted for in the past. It is about voting in the national interest; voting for the future.”

Stressing how every vote will strengthen her negotiating hand in Brussels, Mrs May will say: “We have seen Chancellor Merkel’s comments today; she says the UK has ‘illusions’ about the process and that the 27 member states of the European Union agree. We can see how tough those negotiations are going to be at times.

”Yet our opponents are already seeking to disrupt those negotiations at the same time as 27 other European countries line up to oppose us. That approach can only mean one thing: uncertainty and instability, bringing grave risk to our growing economy with higher taxes, fewer jobs, more waste and more debt.

“So we need the strongest possible hand, the strongest possible mandate and the strongest possible leadership as we go into those talks,” the PM will add.

For Labour, Andrew Gwynne, its campaigns co-ordinator, said: “Theresa May is going to extraordinary lengths to blinker the British public and make this election about anything other than her record in government. The people of Leeds won’t be fooled: the only party of working people is the Labour Party.”

He said under the Tories working people had picked up the bill while those at the top had received tens of billions of pounds of tax breaks; wages had stagnated, public services had suffered huge cuts and the NHS was in crisis.

“It is clearer than ever that the Tories are for the few, not the many. Rather than uniting the country and tackling the challenges we face, their policies are divisive and are taking us backwards,” he added.

Earlier Mr Johnson targeted the Labour leader in an article for The Sun when he said: “The biggest risk with Jeremy Corbyn is that people just don't get what a threat he really is. They say to themselves: he may be a mutton-headed old mugwump, but he is probably harmless."

At a time when Russia was "interfering blatantly with European democracies", Kim Jong Un was leading a "semi-deranged" regime in North Korea and the UK and its allies were taking on an "Islamist death cult", it was "absolutely vital for Britain's security that we have the strong, stable and decisive leadership of Theresa May," said Mr Johnson.

Responding to the comments during a campaign visit to Harlow in Essex, Mr Corbyn said: "We're eight days into the election campaign and the Tories have reduced to personal name calling. I've never been involved in that and never will be.

"We're in this election because we have a serious debate to be held on all the issues facing this country, such as housing, schools, health...We approach this in a responsible, serious way, I leave that kind of language to others."

On the stump, the Labour leader promised a "properly housed" country as he unveiled research showing Labour councils in England had built an average of nearly 1,000 more homes since 2010 than their Tory counterparts.

"A Labour government won't stand by and watch the housing crisis get worse," he said.

"We will build a million homes over the period of a Parliament, half of which will be council and housing association for rent and be totally affordable, because that is the Labour way."

Elsewhere, Tim Farron, campaigning in Liberal Democrat target seat Cambridge, said his party would stop rough sleeping by reinstating housing benefit for under-21s, increasing funding for local authorities and putting long-term homeless people straight into independent homes rather than emergency shelters.

"It is a national scandal that so many people are sleeping on the streets in 21st century Britain," said the Lib Dem leader.

"Under this Government, homelessness has soared and the stripping of young people of housing benefit threatens to make matters even worse," he added.