LONDON • Britain's leadership front runner Boris Johnson has admitted that he did not know the full details of an international trade rule that he is proposing as a viable Plan B for Brexit.
Mr Johnson was grilled in a BBC interview about a measure that he argues could help Britain's economy cope if the country leaves the EU without a deal on Oct 31.
He argued that Britain could continue to trade tariff-free with the European Union under Article 24 of the Gatt (General Agreement on Tariffs and Trade) - but both the EU and the World Trade Organisation have said it would not work in the event of a chaotic Brexit.
"How would you handle paragraph 5C?" the interviewer asked.
Mr Johnson responded: "I would confide entirely in paragraph 5B."
"Do you know what's in 5C?" the interviewer asked.
Mr Johnson paused, before replying: "No."
Mr Johnson is ahead in polls of grassroots Conservatives who will choose the next party leader. The party's members are overwhelmingly in favour of Brexit and regard Mr Johnson as more likely to deliver on the referendum result of three years ago than his rival, Foreign Secretary Jeremy Hunt.
But the interview on Friday highlights Mr Johnson's weak spot - his critics say he is bad on details and has made blunders when he was foreign secretary by not being well enough prepared.
The BBC's Andrew Neil conducted twin interviews with the leadership rivals on Friday evening.
During the exchanges, Mr Johnson said it would be "insane, now", to say the government might not deliver Brexit by Oct 31, in a hint that he could be prepared to accept a delay at a later date.
Mr Johnson said he did not think it will be necessary to suspend Parliament to drive through a no-deal Brexit against the wishes of politicians, while refusing to rule it out.
He also denied that his failure to back British ambassador to the US Kim Darroch prompted the envoy to resign over leaked cables detailing his views of President Donald Trump. That came as British police opened an inquiry into the leak.
Mr Hunt, on his part, refused to guarantee Britain will leave the EU before Christmas, though he said he expected Brexit would be completed by then.
"I'm not going to give you those commitments," Mr Hunt said in the BBC interview. "Prime ministers should only make promises they know they can deliver."
Mr Hunt also said that Parliament may opt to rule out a no-deal Brexit, complicating any commitments around the deadline.
"If we get a deal, it will be on or around 31st October but I can't control what Parliament does and that's why I'm being honest with people," he said.