SIR KEIR STARMER is finding out that his impressive parliamentary majority is more or less unimpregnable. Except, that is, when the forces assaulting his majority are Labour MPs.

First skirmish took place when several of his MPs voted against his government, and more abstained over a vote to lift the cap on benefits that restricts support to a family’s first two children and no more. It was the SNP, somewhat revived on their own turf, that raised the issue.

The fallout created a dissident group of leftish MPs sitting independent of Labour alongside a further group, most notably including Jeremy Corbyn, who were elected independent of Labour support but, naturally, with the active support of thousands of Labour voters.

Labour voters, or rather the missing millions of Labour voters, are Sir Keir’s problem.

Over the last few elections, Labour has managed to shed getting on for three million people who voted for Labour’s most radical manifesto in uncounted decades.

Since then, if the opinion polls are at all accurate, millions more have vanished, some to abstention (Labour’s perennial problem when led from the right) and in today’s particular circumstances, to Nigel Farage’s opportunist play for every discontent.

Today’s revolt is over the government’s bid to give the Department of Work and Pensions the power to raid people’s bank accounts and cancel driving licences as the tool kit of a repressive crackdown on welfare fraud and overclaiming.

This police state power to recover an estimated annual £9.7 billion in benefit overpayments made by the DWP, whether due to fraud or error, is lifted directly from the Tories’ playbook.

This latest revolt revives memories of the revolt last September when the whips forced through cuts to the winter fuel payment for pensioners.

Then dozens of Labour MPs defied a three-line whip, and although only one Labour MP voted against the scheme, with many rebels unwilling to follow the first group of rebels out of the Parliamentary Labour Party, another 50 abstained.

Today, Amnesty International delivered a decisive put-down of the government’s social security and welfare policy: “Lives are being ruined by a system that is consciously cruel — it erodes dignity by design. We are in a state of severe human rights violations.

“The social security system is impenetrable, inadequate and, for some, completely inaccessible.”

The reality is that for millions, every encounter with the state is a nightmare, the roots of which lie in the common ideology of successive governments that the over-riding priority is to appease the money-men, defer the disapproval of the bond markets and cleave tightly to fiscal “responsibility.”

Labour’s responsibility to meet the obligations of its now increasingly absent working-class electorate is abandoned, but the magic money tree has been located in time to fund a war.

With Donald Trump laying waste to bourgeois economic orthodoxy, people may have cut Starmer some slack. But he seems to be running on empty, struck dumb by his inability to face reality and living in a dream world.

He has now confirmed that his hitherto firm opinions about the ways in which we might distinguish between men and women were only provisional and that he now requires the Supreme Court to clarify his thinking about anatomy.

His other exercise in magical thinking concerns his joint project with that other fantasist, French President Emmanuel Macron, to situate a military coalition of the willing somewhere between the fast-shrinking and beleaguered Ukrainian army and their Russian opponents. But we can trust Vladimir Putin when he says that Nato troops on his border, no matter what they claim to be doing, means war.

Starmer has lost the confidence of Labour voters and is on the slippery slope with Labour MPs who fear a wipeout next time they face the electorate.