Former British Prime Minister Tony Blair is pressing his long-held view that voters should be given a chance to re-think Brexit once plans for Britain’s departure from the European Union are clear.

Blair said on January 4 that the Labour Party he led for 13 years should be actively challenging Brexit rather than going along with plans laid out by Prime Minister Theresa May and her Conservative Party allies.

May’s government is negotiating exit plans and the outlines of a new trade relationship with the EU with an eye toward departing the bloc by a March 2019 deadline.

As reported by the Associated Press (AP), Blair and other opponents argue that voters should be able to review these terms and decide whether to go ahead rather than be bound by the 2016 referendum, which saw Britons back Brexit by a four-point margin.

“I’m simply saying one very, very simple thing, which is that in 2016 you knew you wanted to get out of the European Union but you didn’t see the terms of the alternative relationship,” Blair told the BBC radio. “If when you see those terms you think it is better to stick with Europe you are entitled to have that say.”

Blair, the only Labour leader to win three consecutive general elections, said Labour leader Jeremy Corbyn’s pro-Brexit strategy is misguided.

He said Corbyn and Labour should instead be branding the withdrawal from the EU — which started with a referendum called by Conservative Prime Minister David Cameron to ease party divisions — as “the Tory Brexit” to capitalise on growing public doubts about the process, caused in part by Britain’s slowing economic growth.

In an article on his website, Blair said Labour should challenge May every week at prime minister’s question time by asking why the Conservatives are “weakening our country.” That approach is only credible, he said, if Labour is clearly opposed to Brexit.

According to AP, Blair’s political stock fell dramatically with public opposition to his decision to join the US-led invasion of Iraq, and there are no indications that his opposition to Brexit is gaining traction within the party, which has moved sharply to the left since making Corbyn its leader in 2105.

In a separate report, the Reuters news agency noted that opinion polls show little sign of a change of heart among voters on Brexit and it is unclear how it could be stopped if both major political parties support the divorce.

Supporters of Brexit accused Blair of undermining both Britain’s negotiations with the EU and the will of the people.

“Blair and his elitist gang are damaging our negotiating strength, thus damaging our national interest by their continuing efforts to undermine democracy,” said Richard Tice, who helped found one of the two Leave campaign groups.

“History will not forgive them,” Tice told Reuters.