Having reached the Labour leadership ballot courtesy of the Fire Brigades Union yesterday, Rebecca Long-Bailey has secured her fourth affiliate endorsement by winning the support of the Communication Workers Union.

That the last of the big four trade unions to nominate has plumped for the shadow business secretary is not unexpected: the CWU, after all, was the first union to back Jeremy Corbyn in 2015. It is nonetheless a testament to the strength of Long-Bailey’s appeal among the organised Corbynite left: the CWU’s nomination process, which brought together its hundreds of local branches in a mass vote, was the most democratic of any union’s.

The same cannot be said of the other fully-fledged Corbynite vying for a top job, Richard Burgon. The narrow margin of his victory over Angela Rayner at the FBU executive yesterday – a body that shares his enthusiasm for the current leadership – suggested he did not have the same appeal to left activists as Long-Bailey.

So it has proved, with the CWU becoming the first affiliate to nominate Long-Bailey alongside Rayner, the woman she insists – even if the tastes of the left suggest otherwise – is her real running mate.