“It never occurred to me when I was Foreign Secretary,” says David Miliband, addressing his audience at the United Synagogue, “that people were looking at me and saying: ‘He’s a Jewish Foreign Secretary’. It never occurred to me that, when I was speaking, it was my religion that was in the front of people’s minds.”

It has been “painful” for the former Labour minister to discover the depths of anti-Semitism that exists in the UK, he says, and how his party has become “a magnet for some people with some utterly repulsive views” since Jeremy Corbyn became leader, resulting in some MPs quitting.

The members of Miliband’s Jewish community, here in Highgate, north London, share that pain. The mood is sombre as he delivers a lecture on Brexit, fake news and the challenges facing British democracy in tribute to the late historian Sir Martin Gilbert.

Miliband, 54, is usually an observer rather than a protagonist in UK politics these days. Those on the Left of the Labour party may say good riddance to the Blairite who was the favourite to win the party leadership in 2010 yet failed to inspire and lost to his brother, Ed. Others will agree with the actor James Corden, who tweeted yesterday: “I truly believe the day David Miliband left British politics it all started to unravel.”

Fighting anti-immigrant populism

Miliband’s passion is still evident when he sits down with i ahead of his lecture, in his capacity as the CEO of the International Rescue Committee, the New York-based aid charity he has run as CEO since 2013.

He has been moved this week by the discovery of 39 Chinese people discovered frozen to death in a refrigerated lorry in Tilbury Docks. While it appears they were not refugees, it’s a reminder of the risks that many asylum seekers and economic migrants take to enter the country – and Miliband is damning about the anti-immigrant “hostile environment” strategy introduced by Theresa May while she was Home Secretary, and Donald Trump’s incendiary policies and racist rhetoric.

The story “should be a call on conscience to make a difference to desperate people”, he says, “in a world that is putting walls up rather than offering help”.

“The higher you build the walls, the more the people smugglers will work to get around them – and the more desperate, and the more that people will pay, to get around them.”

‘Rescuing Futures’

We met at the HQ of the Citi investment bank in London’s Canary Wharf, where his charity is announcing the expansion of its Rescuing Futures partnership with the bank’s charitable foundation. It will provide $3.5m to fund business training, mentorship and start-up grants for refugees and vulnerable people in six cities around the world.

David Livingstone, CEO of Citi Europe Middle East and Africa, speaks movingly of meeting an “inspiring” shoemaker named Lydia two weeks ago in Yola, Nigeria. She and her children had to flee armed groups who arrived in her town, leaving her with no money or possessions. But has been trained to help set up her own shoemaking business.

He adds: “We’re living in an age when governments are in retreat, and so it’s incumbent on us as an NGO to step up, but we want to step up with the private sector.”

Miliband has been criticised for being paid $911,796 (£741,883) by the charity, a sum that has risen by $240,047 in the last two years. The 12 top-paid staff at the IRC take home $5m.

Unsurprisingly he does not discuss the ethics of this, saying only that he doesn’t decide his own salary. “We have independent mechanisms to set pay – that’s the right thing to do – and it’s run by the independent board of directors.”

Where should the UK go now with Brexit?

Miliband tells i that the UK should hold a second referendum on Brexit “for the democratic health of the country”.

In light of Boris Johnson’s proposed deal with the EU, “now we know what Brexit means,” says Miliband, who supports Remain.

He is dismissive of Labour’s claim last year that it could secure a “Jobs-First Brexit”, saying in his lecture that it was “a vain hope at best and a deception at worst. The only jobs in a Jobs-First Brexit are jobs for Holland, Germany and France”.

He also advocates the creation of a written constitution for the UK, to remove the Queen from politics, after “a near-miss event with our parliamentary democracy” with Johnson’s attempt to prorogue Parliament.

He refers to himself as an “ex-politician” at the synagogue, but does not rule out a return to UK politics. “I don’t know what I’m going to do next but I know what the test is: it’s where I can make the most difference for the things I believe in.”

As for the leadership of Labour and its future, he says: “There are so many talented people in the Labour Party… I wish they had more power.”