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.