LABOUR’S very own Lord Voldemort has returned. “He who cannot be named” — the party actually suspends members who use “Blairite” as an insult — is back. And with typical contempt for popular opinion, our ex-PM has put blocking Brexit at the top of his agenda.

Busy setting up shiny new offices near Westminster, Tony Blair told the New Statesman last week that leaving the EU “can be stopped if the British people decide that, having seen what it means, the pain-gain cost-benefit analysis doesn’t stack up.”

But of course, no-one can see what Brexit “means” until it actually happens. Blair just wants to scare us into a second referendum — something even the majority of Remainers are against, according to YouGov polling.

From his interview, it’s clear who the real target is. Blair insists Jeremy Corbyn’s “populism of the left” is doomed to lose the “debates around culture and identity,” warning that unless Labour returns to the “progressive centre” it will “just get beaten bigger.”

But the evidence suggests he’s completely wrong. After years of failing to deliver lasting social and economic justice while in power, the discredited centre-left is getting hammered at ballot boxes all over the world.

Donald Trump’s shock victory over Hillary Clinton may be the latest example of this — but, barring a miracle, French voters will face an even-more-awful choice between the centre-right and bona fide fascists in next spring’s presidential election.

The ruling Socialist Party looks likely to be knocked out in the first round, perhaps partly due to its leader’s lurch to the right and willingness to bomb countries in the Middle East and Africa.

Back on this side of the Channel, our own centrist war criminal finds it “bizarre” that Labour members “want to blame those of us who won elections for the defeats we’ve subsequently suffered,” conveniently forgetting the five million voters who deserted the party during his premiership — many of them over the Iraq war. Like much of the political Establishment, he’s totally out of touch with the public — Brexit being the most blatant example. And framing this complex issue around “culture and identity” instead of class interest is a gift to far-right parties such as Ukip, which is working hard to park its tanks on Labour’s lawn, especially in the long-abandoned heartlands.

That was always the danger with an official Labour In campaign too closely aligned to the Tories — a trap Corbyn deftly avoided, though his party’s right hated him for it.

And although much of Labour tried to blame his nuanced “remain and reform” argument for their referendum failure, a new book by Sunday Times political editor Tim Shipman reveals what the real problem was.

“Labour MPs backing Remain reported back that they were not campaigning in their own seats, having been shocked at the Eurosceptic reception they received on the doorstep,” he writes in All Out War.

Clearly a simplistic “EU is great” message wasn’t cutting through — and it seems their obsession with ousting Corbyn was another factor behind the party’s unimpressive performance.

One Remain campaign staffer told Shipman that “Labour was just consumed by what to do about Jeremy,” adding: “They couldn’t bring themselves to focus on the campaign.”

So the idea that Brexit was in any way Corbyn’s fault — and remember that was the pretext for the Blairites’ failed coup and resulting leadership contest — is just another example of what’s now known as “post-truth,” Oxford Dictionaries’ word of the year.

According to the publisher, the EU referendum and US presidential election were good examples of “circumstances in which objective facts are less influential in shaping public opinion than appeals to emotion and personal belief.”

And although Labour has launched its own investigation into the growing online “fake news” phenomenon, last week saw a new post-truth low from the mainstream media.

“Did neonazi murder Jo over fear he’d lose council house he grew up in?” asked the Daily Mail after Thomas Mair was found guilty of assassinating Labour MP Jo Cox.

No he didn’t, but the Mail’s headline unhelpfully continues: “Terrorist thought property could end up being occupied by an immigrant family — and the MP wouldn’t help him.”

Now, none of this came up at the trial — and the article even admits it’s based on gossip from neighbours.

But the baseless insinuation that Cox had somehow let her constituent down is designed to take on a life of its own, repeated in right-wing circles until it becomes accepted wisdom.

Housing worries were not the trigger for this horrific assassination. The judge was clear that “this murder was done for the purpose of advancing a political, racial and ideological cause, namely that of violent white supremacism and exclusive nationalism most associated with nazism and its modern forms.”

But the Mail completely ignored this in its report. Neither did it mention Mair’s mid-crime cries of: “Britain first — this is for Britain!”

Not to be outdone, both the Sun and the Mirror shared the same headline: “Jo Cox murderer Thomas Mair became deranged white supremacist after mum left him for black boyfriend.” But again, this is deliberately misleading and designed more than anything to stoke up social tensions. There’s no evidence that Mair’s neo-nazism had anything to do with who his mum dated, but that doesn’t stop the gutter press from tacitly blaming multiculturalism for the terrifying resurgence of the far right.

Missing from this narrative are the reckless politicians — and media proprietors — who exploit widespread fear and anger over widening inequality to turn the working class against itself.

Although Mair assassinated Cox just one week before the referendum, this was hardly mentioned during his trial. But the hate-filled nature of the Brexit debate — exemplified by the infamous “Breaking Point” posters unveiled by Nigel Farage just hours before the killing — was surely relevant to Mair’s state of mind.

The trial avoided any discussion of the reasons why he murdered the prominent Remain campaigner, who had been filmed facing down a Ukip-led flotilla near her houseboat on the Thames the day before her death.

But by giving his name as “death to traitors, freedom for Britain” at his first court appearance, Mair makes it clear exactly where he stands in Blair’s “culture and identity” wars.

The “progressive centre” simply has no answers for countering the far right’s fury, which feeds on the soft left’s failure for decades to defend workers, communities and the state itself from corporate plunder while in power. Blair’s bad decisions have instead fueled extremism both in Britain and abroad, so it’s hardly surprising that no-one takes him seriously anymore.

Instead, Labour has a last chance with Corbyn to reframe the political debate away from illusionary “culture and identity” and back to actual politics.

If enough people realise that rising poverty is caused by corporate greed and compliant governments, not immigrants and the unemployed, this will undercut support for the far right. And free from EU restrictions on renationalisation and massive state investment, Labour can now offer a socialist “New Deal” that leaves no-one behind — the only way to truly defeat fascism once and for all.

• Chat to Charley on Twitter: @charleyallan