The Labour leader was accused of having “done a deal” with the SNP to secure power by offering a second Scottish independence referendum - a claim he dismissed as “nonsense”.
And Mr Corbyn was repeatedly challenged by the Prime Minister to say if he would campaign to stay in the EU or back a re-negotiated Labour deal with Brussels in a second Brexit referendum.
Mr Johnson was confronted over the government’s plan to strike a trade deal with the EU by the end of 2020, with his Labour opponent telling him: “You’re not going to get it done in a few months, and you know that full well.”
The Prime Minister and Labour leader shook hands on a pledge to improve the tone of the UK’s angry political discourse, but spent large parts of last night’s one-hour head-to-head debate talking over one another and accusing each other of lying.
A snap YouGov poll on reaction to the debate scored it as a stalemate, with 51% of those asked saying Mr Johnson had won, and 49% believing Mr Corbyn performed better.
In a first half dedicated to Brexit, Mr Corbyn accused the government of entering into secret talks to “sell out our health service to US big pharma” in a future trade deal.
Mr Johnson hit back, dismissing the claim as “an absolute invention” and accusing the Labour leader of trying to disguise the “void” at the heart of his Brexit policy.
“Mr Corbyn, you’ve heard tonight, cannot answer the fundamental questions,” the Prime Minister said. “Is he for Remain or Leave and what price would he pay to secure Nicola Sturgeon’s support to enter Number 10?”
Challenged over allegations of anti-semitism within the Labour Party, Mr Corbyn insisted that “anyone who has committed any anti-Semitic acts or made any anti-Semitic statements [has been] either suspended or expelled from the party... we do take this very, very seriously indeed.”
When asked about “telling the truth in politics”, Mr Johnson attacked Mr Corbyn’s leadership and said: “It’s a complete failure of leadership what’s happened with anti-Semitism, but the failure of leadership is even worse when you look at what is happening on their Brexit policy.”Indyref2Mr Corbyn insisted there would be “no deal with the SNP [and] no support for a Scottish referendum in the early years of the next Labour government”.
The Labour leader added that it was “their choice” if the SNP leadership “chooses to put the Conservative government back in office” and forgo £70bn of planned investment in Scotland.
Mr Johnson replied: “I listened very carefully as I always do to Mr Corbyn - I didn’t hear him say he was going to rule out a referendum on Scotland. Did you?”
Asked whether the Union was “worth sacrificing for Brexit”, the Prime Minister said it was “of course, the most important thing. It’s a fantastic thing.”
Mr Corbyn said the Prime Minister’s proposed Brexit deal was “about creating a border between the Republic of Ireland and Northern Ireland, and creating a different customs arrangement for Northern Ireland with the rest of Ireland, having promised to the Democratic Unionist Party he would never do that.”
Nicola Sturgeon and Jo Swinson did not take part after the SNP and the Liberal Democrats failed in a legal bid to force their way into the head-to-head debate.
Following the debate, Ms Sturgeon said 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.”
Scottish Conservative interim leader Jackson Carlaw claimed Mr Corbyn’s failure to say that the Union was more important than Brexit was “incredibly revealing”.
“He didn’t campaign in Scotland during the independence referendum and he has shown again tonight that he thinks Scotland is expendable.
“Quite simply, If Mr Corbyn becomes Prime Minister, the Union is in immediate danger.”
Liberal Democrat candidate for Edinburgh West, Christine Jardine said Mr Corbyn had “refused to rule out Indyref2 [and] also refused to commit his party to campaign for Remain”.