BORIS Johnson accused Jeremy Corbyn and Nicola Sturgeon of having “probably already done a deal” on a second Scottish independence referendum as the leaders of the two main UK parties clashed on prime-time television for the first time.

In the first of two campaign head-to-heads, the Labour leader rubbished the Prime Minister’s claim of a Lab-SNP coalition, branding it “nonsense” and insisting no deal had been done or would be done.

During the hour-long debate on ITV in Salford the two leaders clashed not only on the Union but also on Brexit, the NHS, the monarchy and the economy as well as facing a question about Prince Andrew.

The audience applauded approvingly and laughed mockingly at both men in equal measure as neither landed a knock-out blow.

After the programme, a snap YouGov poll gave Mr Johnson the edge, saying viewers – excluding the don’t knows – believed the PM had won the debate 51 per cent to 49.

Earlier, it seemed the greater onus to do well was on Mr Corbyn as a Kantar poll gave the Tories a significant 18-point lead.

The survey undertaken this week placed the Conservatives on 45 points, up eight from last week, Labour unchanged on 27, the Liberal Democrats down one at 17 and the Brexit Party down seven on just two.

The two party leaders who were not in the TV studio, having failed in their court action to be there, reacted negatively to their opponents’ performances.

Ms Sturgeon said she was "not impressed at all" by the debate and insisted neither men were "fit" to be Prime Minister.

“The clear takeaway for Scotland from this debate is that neither of these men should be able to determine Scotland's future.

“Jeremy Corbyn can’t decide if he is Leave or Remain and Boris Johnson is determined to take Scotland out of the EU against our will,” said the First Minister.

READ MORE: Nicola Sturgeon slams Jo Swinson for 'disgraceful response' to nuclear weapons question 

Jo Swinson, the Liberal Democrat leader, said viewers deserved so much better than the bluster and diversion on offer from the “two old tired parties”.

She added: “Both people on that stage want Brexit and there was no one on that stage arguing to remain in the European Union. Staying in the EU is better for our economy, better for our environment, and better for our NHS.”

As Mr Johnson and Mr Corbyn clashed on the Union, the latter responded to pressure by telling his opponent: “There is not going to be a coalition between Labour or anybody else. There are no deals that have been done and there will be no deals that are done.”

But Mr Johnson urged the audience to be in no doubt that to secure the keys to No 10 Mr Corbyn and Ms Sturgeon would do a deal.

“They probably already have done a deal with Nicola Sturgeon and the SNP to form a Corbyn-Sturgeon coalition,” declared the PM, stressing: “And the price of Nicola Sturgeon’s support – she has made it absolutely clear – will be a second referendum on the Union with Scotland.

“I don’t think we need another one, we had one in 2014; the people of Scotland voted very substantially to stay in the most successful political partnership in the last 300 years. Why put this great country through another referendum in Scotland,” the PM said to applause.

But Mr Corbyn repeated there would be “no deal with the SNP,” stressing: “There will be no support for a Scottish referendum in the early years of the next Labour Government because I want to invest in Scotland and give it £70 billion it needs in capital investment.

“If the SNP choose to put the Conservative Government back in office with its austerity programme that’s their choice,” said the Labour leader.

But Mr Johnson pointed out how he had listened very carefully to Mr Corbyn and noted: “I didn’t hear him say he was going to rule out a referendum on Scotland. Did you? We are ruling out a referendum. It’s perfectly clear the price of Nicola Sturgeon’s support for a chaotic coalition is a second referendum.”

Asked if he could rule out a second referendum, the Labour replied to applause: “We’ve had five years of a chaotic coalition already.”

Earlier, the two leaders clashed on Brexit.

READ MORE: Boris Johnson: I'll never debate Sturgeon and I'll never agree to a second Scottish independence referendum 

Mr Johnson promised to "end this national misery" and argued Labour offered "only division and deadlock".

While Mr Corbyn insisted Labour would "get Brexit sorted by giving you, the people, the final say".

He dismissed the Tory leader’s pledge to "get Brexit done" by the end of January as "nonsense".

But Mr Johnson told the audience: "If you vote for us, we have a deal that is ready to go. Approved by every one of the 635 Conservatives candidates standing at this election.

"As soon as we can get that deal through Parliament, as we can in the next few weeks, we can get on with the people's priorities."

But Mr Corbyn retorted that he could not deliver on what he was promising.

"That idea that the Prime Minister Boris Johnson' deal can be dealt with and finished by the end of January is such nonsense," he declared.

"What he is proposing is a trade deal which will take at least seven years to negotiate whilst at the same time saying he will negotiate a special trade deal with the European Union. The two things are actually incompatible."

Mr Corbyn defended Labour's strategy to negotiate a new deal with the EU within three months of taking office and then put it to voters in a referendum within six months.

However, he was taunted by Mr Johnson over his refusal to say which way he would vote, saying there was a “void at the heart” of his Brexit policy: "Are you going to campaign for Leave or Remain?"

The Labour leader hit back accusing him of conducting secret meetings with the US about opening up the NHS to American companies in a future trade deal, producing a heavily redacted document.

Mr Johnson, however, said the claim was "an absolute invention," insisting: "It is completely untrue. There are no circumstances whatever in which this Government or any Conservative government will put the NHS on the table in any trade negotiation."

On the monarchy, the Labour leader said it needed a “bit of improvement” while the PM insisted that as an institution it was “beyond reproach”.

Asked about the Prince Andrew saga, both men expressed sympathy for the victims of Jeffrey Epstein. “There are very serious questions that must be answered and nobody should be above the law,” insisted Mr Corbyn while Mr Johnson added: “The law must certainly take its course.”

At one point, in response to raising the tone of political debate, the two rivals shook hands.

By the end, they were asked what Christmas present they would give each other. Mr Corbyn suggested A Christmas Carol so the PM could find out about Scrooge while Mr Johnson offered his opponent a jar of damson jam.

Earlier, after Mr Johnson made clear in an interview with The Herald that he would never debate Ms Sturgeon, she branded him a “big scaredy-cat”.

Noting how when the PM visited Bute House in the summer he appeared to be up for a debate on Scottish independence, the FM said she did not know why he had changed his mind.

"If you want to be Prime Minster, as he is standing in this election to be, then he shouldn't be running scared from debate and it speaks volumes that he is so frightened of debating anybody other than Jeremy Corbyn.

"But I'll put down a challenge to him right now: I'll debate him any time, any place. So come on Boris, stop being so scared," declared Ms Sturgeon.

In other developments:

*the Lib Dems will today launch their election manifesto in London, pledging south of the border to spend £10bn more a year on schools and hire 20,000 more teachers by end of next Parliament – this would give the Scottish Government an extra £1bn a year under the Barnett Formula;

*Labour today vows to “wage war on poverty” and reverse the damage of a decade of austerity with the publication of its report, Poverty Britain, highlighting 10 ways the Tories have failed to tackle poverty but entrenched hardship in society – it prompted the Conservatives to set up what they termed a “Labour lies unit” to call out what they insisted were false claims and statistics frequently peddled by the Opposition;

*the Green Party launched its manifesto, saying it would invest around £100bn a year in tackling climate change, including legislation for a "green new deal" intended to set Britain on track to reduce carbon emissions to net zero by 2030;

*Labour’s John McDonnell signalled Labour might be moving towards writing off tens of billions of pounds of student debt in England and Wales as he said his party in government would “rewrite the rules” of the economy and impose an “excessive pay levy” on big business and

*the PM said he would "come down hard on knife crime in London" by giving increased powers to police to stop and search as well as promising "three-times-faster charging and prosecution" for knife offenders with anyone caught, arrested and charged within 24 hours and in court by the end of the week.