KEIR STARMER is a dead man walking. His fake indignation at Peter Mandelson convinces no-one: claiming he believed in the integrity of a man nicknamed “the Prince of Darkness” would be a tough sell even if Starmer hadn’t such a track record of dishonesty himself.

The Prime Minister has form on pretending he never said things he’s said. He’s still at it.

In the Commons on Wednesday he admitted that he knew Mandelson continued to associate with Epstein after the latter’s conviction on a child sex offence. He had to: the Financial Times broke that story in 2023 and it was brought up by critics (including this newspaper) when Mandelson was named a likely ambassador to the US in 2024.

Yet today he dissimulated, referring to “information that was not known at the time of his appointment… before he was appointed ambassador… he was asked whether he had stayed with Epstein after his conviction.” That was already a matter of record.

Few MPs are still prepared to defend the PM. He remains in office because those who want to challenge him — and they had plans to do so before this — would rather wait. Nobody wants responsibility for the local election results in May, or what looks likely to be a self-inflicted humiliation in Gorton & Denton later this month. One prominent candidate, Wes Streeting, has also been close to Mandelson for years and could be caught up in the fallout.

That fallout is potentially existential for Labour, because Mandelson’s role in reshaping the party from the 1980s on has been so pervasive.

His resignation from it is — as Communist Party leader Alex Gordon put it — like “a man resigning from his own shadow,” having transformed a party that was once a huge social as well as political force in British life into “a corporate career-ladder dominated by vicious right-wing sectarians.”

Revelations published by the i newspaper, indicating that Mandelson played a role in vetting (and vetoing) parliamentary candidates ahead of the 2024 election, underline it again, as do Solomon Hughes’s regular exposés in the Morning Star (more in his column tomorrow) on the revolving door between political office and corporate cashing-in. Today’s Labour is to a huge extent moulded in Mandelson’s image.

If it is to survive, the surgery will have to cut deep. This is not a matter of one man’s corruption but an entire political culture, and breaking with Mandelson’s politics must be the start.

Since it was his ambassadorship that has blown up in Starmer’s face, and everyone knows he was appointed to fawn on Trump because of, not despite, his lifetime of schmoozing the “filthy rich,” we can start there.

Trump himself clearly has questions to answer based on the Epstein files, besides his lawless aggression from the Caribbean to the Persian Gulf. How can Labour justify continuing subservience to the White House, helping it seize ships in international waters, echoing its threats against Iran? Every Labour MP should be put on the spot.

Then, when Starmer goes, will we see an overdue revolution against New Labour, a Blair-Mandelson project from the off? Starmer changed the rules to raise the bar impossibly high for a left candidate to run in the heavily purged and carefully vetted (by Mandelson!) parliamentary party. But few anticipated a crisis of this magnitude.

MPs should be pressed to back a serious challenge to the party’s right, one who can credibly turn its back on genocide apologism, privatisation and sleaze.

This may prove an ask beyond today’s parliamentary party.

Well, alternatives are gaining ground, and Labour can’t assume working-class voters have nowhere else to go (another hallowed Mandelson strategy).

Gorton & Denton could prove another Caerphilly, where they were beaten simultaneously by parties to their left and right. If Labour cannot throw off Blairism it is doomed, and nobody can say it wasn’t warned.