Remainers must “face up to one simple point: we lost”, Tony Blair has told the New Statesman ahead of the UK leaving the European Union tomorrow (31 January).

In a wide-ranging interview with the Spotlight policy supplement – available in full in this week’s NS – the former Labour prime minister, an ardent champion of Remain since the 2016 EU referendum, said it was a “terrible mistake to ever agree to a Brexit general election, as people like me tried to tell the Labour Party and the Liberal Democrats”.

He added: “But we did it, we paid the price for it. We've lost the debate and Brexit is now going to happen.”

Ahead of the UK entering a Brexit transition period until the end of 2020, Blair said it was now time for Remainers to “pivot to a completely new position...We’re going to have to be constructive about it and see how Britain develops a constructive relationship with Europe and finds its new niche in the world.”

Blair argued that, following its fourth consecutive general election defeat, Labour was facing a “fundamental problem”. He said: “The thing I would emphasise more than anything else is that we’ve got to redefine the word ‘radical’, because what the Labour Party – and not just the Labour Party, we see this around the world – puts forward as radical today is not actually radical, it’s small-C conservative.”

Asked whether Boris Johnson was doing a good job as prime minister, Blair replied: “I wish that… we didn’t have a Tory government, but my anxiety at the moment is that Labour learns the lessons of defeat.

“It’s got to learn those lessons properly otherwise we are going to carry on having Tory governments.” Blair noted that the 120th anniversary of the Labour Party’s creation was approaching in February. “It will be a time for reflection about how many years of that 120 the Labour Party has spent in government.”

As he discussed a new counter-extremism initiative from his Institute for Global Change, Blair said the only way to ultimately defeat violent, ideological terrorism was through education. “In the end you've got to destroy the idea,” he said.

See this week’s New Statesman for the full interview in our special Spotlight policy supplement, or read it online