Jeremy Corbyn has said he would remain neutral in any second Brexit referendum.
The Labour leader has pledged to negotiate a new exit deal with the EU and put it to a public vote within six months of taking office.
He has repeatedly refused to say whether he would campaign to Leave with his deal or for Remain.
But speaking during a BBC Question Time election special on Friday evening, Corbyn said: “I will adopt as prime minster, if I am at the time, a neutral stance.”
He said this would allow him to “credibly carry out the results of that to bring our communities and country together”.
Pressed to clarify that he would not take a side, Corbyn said: “Yes.” He added: “First heard here on Question Time.”
Boris Johnson, appearing on the programme later, said he did not see how Corbyn “can do a deal” with the EU if he was “going to be neutral.”
The audience laughed and groaned when the prime minister said MPs were “given every opportunity” to pass his Brexit Bill. “They passed a law to insist that extended beyond October 31,” Johnson insisted.
“Let’s be in no doubt, I didn’t want to have an election. No prime minister wants to have an election on December 12. We had to do it because Parliament is blocking Brexit.”
The prime minister also refused to apologise over his use of language and defended Tory austerity.
Johnson was asked to apologise and admit he had personally contributed to “racist rhetoric” during his journalistic work.
He was challenged him for comparing veiled Muslim women to “letterboxes”, referring to “watermelon smiles” and “flag-waving piccaninnies” and to “tank-topped bum boys”.
the PM said: “I have written many millions of words in my life as a journalist and I have… genuinely never intended to cause hurt or pain to anybody and that is my intention.”
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Corbyn also indicated he would be willing to permit another referendum on Scottish independence, although not in the “first two years” of his government.
Speaking on the programme after Corbyn, Scottish First Minister Nicola Sturgeon said a referendum would be the price of the SNP supporting a Labour government.
And she doubted Corbyn really would prevent another early vote if it meant he could be come prime minister.
“Do you think he’s going to walk away from the chance to end austerity, to protect the NHS, stop Universal Credit, simply because he wants for a couple of years to prevent Scotland having the right to self-determination?” she said.
“I’m not sure he’s going to compromise the chance to have a Labour government for that issue.”
Lib Dem leader Jo Swinson, challenged over her party’s position on revoking Article 50, said she was being “straightforward as a party that we want to stop Brexit”.
“I don’t think you can accuse us of not being upfront about wanting to stop Brexit. We’ve been crystal clear about that from the very beginning,” she told the Question Time audience.