London- John Bercow, the former House of Commons speaker who oversaw Britain’s bruising parliamentary battles over Brexit, says leaving the European Union would be a historic mistake for the U.K., but it’s not too late to reverse the decision.

Bercow retired last week after a decade running the daily business and debates of Parliament’s lower chamber. In that job he had to be neutral. But he now says that Brexit is the country’s “biggest foreign policy blunder” since World War II, an error that will leave Britain weakened economically and diplomatically.

“We’re in a world of power blocs and of trade blocs,” Bercow told the Associated Press in an interview Thursday. “And it makes more sense for the U.K. to be part of that power bloc called the European Union and part of that trade bloc called the European Union.”

He said “if you add to that the civilizing effect of some of the social legislation that has been ushered in by the European Union, that seems to be to amount to a virtuous combination of benefits for the U.K.”

“I don’t say that (Brexit) will spawn mass poverty, or that we won’t be able to get by, find a way to trade and offer some voice in the world,” he said. “But I think that we will suffer in trade terms and suffer in terms of global standing and influence.”

Some British politicians – even among those who voted in 2016 to remain in the EU – now say the country must honor the result of the referendum. But Bercow says “the best course for the U.K. is to remain” in the EU.

He says Britain’s 2016 referendum to leave the bloc “isn’t the final word on the subject” and would be democratic to hold a new public vote on EU membership.

“In 2016, people voted by a narrow margin for departure, but they didn’t vote for a destination,” said Bercow, who is also stepping down as a member of Parliament after 22 years.

“There wasn’t a consensus and there isn’t a consensus now, and there’s great disagreement as to what sort of Brexit there should be. So it seems to me that if there is a withdrawal agreement, it’s perfectly reasonable, if Parliament wants to do so, for Parliament to say ‘no.’ Or alternatively to say ‘yes,’ but it should be subject to a final decision by the electorate in the form of a referendum,” he said.

Britain is currently in the midst of an election campaign, with all 650 seats in the House of Commons up for grabs in the December 12 vote.

Prime Minister Boris Johnson hard pushed for the early vote after Parliament thwarted his plans to have Britain leave the EU on Oct. 31. Johnson hopes his Conservatives can win the vote, pass his Brexit divorce plan and get the country out of the 28-nation bloc by the next Brexit deadline on Jan. 31.

As speaker, Bercow was accused by some of favoring opponents of Brexit in his decisions. His newfound outspokenness is likely to bolster that view.

Bercow denies bias, and says the criticism doesn’t bother him.

“There will always be people who criticize, and that’s as predictable as the passage of the seasons,” he said. “But that is a matter which occasions me no loss of sleep whatsoever.”

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