Both men are trying to win over voters who are weary about Brexit. Britain is due to leave the European Union on 31 January, after failing to meet a 31 October deadline to approve an exit deal.
The two candidates are also both trying to overcome mistrust. Johnson is under fire for failing to deliver on his often-repeated vow that Britain would leave the EU by the 31 October deadline.
Corbyn is accused by critics of promoting high-tax policies and of failing to clamp down on anti-Semitism within his party.
Both stuck to safe territory, with Corbyn touting Labour’s plans for increases in public spending and Johnson trying to keep the focus on his promise to “get Brexit done.”
Focus on Brexit
Corbyn vowed to renegotiate Johnson's deal and hold another referendum. Half of Britons still oppose the result of the 2016 Brexit referendum.
Johnson, who has promised to implement the exit deal he negotiated with Brussels and take the UK out of the EU by 31 January, said a second referendum would only prolong Britain's departure. He pushed Corbyn several times to say whether his party would campaign to stay in the EU or leave. Corbyn refused to take a side, saying he would honour the decision of the people.
Johnson pledged to secure a trade agreement for Britain's long-term relationship with the EU by the end of 2020. Corbyn said that was a fantasy, saying such deals usually take years to complete.
He also repeated his allegation that Johnson planned to offer parts of Britain’s state-funded health system to American medical firms as part of future trade negotiations with the United States, a claim that Johnson called "an absolute invention."
Even in the polls
After the hour-long debate, polls showed the public evenly split, with 51 per cent saying Johnson won, and 49 per cent for Corbyn, a result that shows that Labour is doing better than previous polls.
The debate featured only two candidates after the High Court in London rejected a legal challenge from the Liberal Democrats and the Scottish National Party, saying that the decision to limit the format to the leaders of the the two largest political parties was a matter of “editorial judgment’.
Two seven-way debates are planned later in the campaign, and Corbyn and Johnson are due to square off again in a BBC debate on 6 December.
