Bankrupt councils have gotten into trouble through profligate spending on loony projects like month-long Pride events and training staff in critical race theory. That might be true, but it is only partially true. Another big factor, it is becoming painfully clear, is equal pay claims – which have cost Birmingham City Council up to £760 million alone. Next in the firing line is Sheffield, where the GMB union claims to have opened the lid on a simmering pot of injustice which it plans to follow up with multi-million pound claims against the council.

Personally, I wouldn’t pay a council diversity officer a tenth of what I would pay a loo-cleaner, but that is, I admit, a personal view

These are not cases where men and women working alongside each other doing the same job are being paid different wage rates – such discrimination has been unlawful for decades. These are claims based on the idea that different occupations involve work of ‘equal value’. Hence, according to the GMB, care managers (who are on grade five of Sheffield City Council’s pay scale) should really be alongside cemetery supervisors, who are on grade seven. Cleaners (grade one) should really be paid the same as caretakers (grade three) and senior teaching assistants should be paid the same as night-time noise officers, whereas in fact they earn £11,383 a year less. This is sex discrimination, protests the GMB, because the underpaid occupations are female dominated.

There are multiple objections to the GMB’s case. Firstly, in a functioning labour market people are paid not according to what value a trade union has put upon their work but according to supply and demand. There may be a very good reason why night-time noise officers are paid more than teaching assistants. There is a clue in the name: the former work antisocial hours. Likewise, you might have to pay a cemetery supervisor more than a teaching assistant because it is a pretty depressing job. As for cleaners versus caretakers, surely the latter involves extra responsibilities – you don’t just push a broom around, you have to look after a building, possibly around the clock. If you are not going to allow a council to pay caretakers more for taking on extra responsibilities then how are you going to persuade cleaners to apply for the posts?

If Sheffield City Council was preventing women from applying for jobs as cemetery supervisors or night-time noise officers, it might be objectionable. But even the GMB isn’t alleging this. It seems to accept the idea that some occupations will always be female-dominated, and that it should be the arbiter of how much a job is worth. But that is an entirely subjective matter. Personally, I wouldn’t pay a council diversity officer a tenth of what I would pay a loo-cleaner, but that is, I admit, a personal view. When you start trying to compare occupations for equal value, though, there is no stopping it. What if night-time noise officers, in turn, decide their work is worth as much as a teacher’s? We will end up with a vicious circle of wage inflation.

Astonishingly, the Equality Act seems to support the concept of sex discrimination on the basis of work of equal value. It has planted a huge bomb underneath the finances of our councils and other public sector bodies – and it is now going off.