Angela Rayner has struck the wrong note on a four-day week

Angela Rayner’s department has dropped its opposition to a local council experimenting with a four-day week for its staff.

The previous Conservative government objected to the trial by South Cambridgeshire District Council, which began last year. But Ms Rayner, who is local government secretary as well as deputy prime minister, accused the Tories of “micromanaging” local authorities.

Now her department says: “Although it is not government policy to support a general move to a four-day working week for five days’ worth of pay, we recognise that local authorities are independent employers who are rightly responsible for the management and organisation of their own workforces.”

An official in the department has told South Cambridgeshire that “local voters are best placed to make decisions about the effectiveness of local authority services in their own areas”.

Of course, this is true, and it must be said that there is no evidence that the council is providing a worse service to its residents as a result of the policy.

However, there are other reasons for being deeply sceptical about four-day weeks in the public sector. Above all, they give the appearance of special treatment for workers who are paid from the public purse. If four-day weeks were common in the private sector, that would not be a problem, but they are not.

Despite well-meaning advocates of the policy pointing to a few examples of where profit-making enterprises have introduced four-day weeks and claim they have benefited from a happier and more productive workforce, they remain rare.

This suggests that the hype about productivity gains is overdone: if they were such a good idea, the ruthless natural selection of market forces would have driven most firms to have adopted them by now.

Which suggests, in turn, that the public sector should be cautious about adopting practices that are likely to be seen as more in the interest of those who provide public services than of those who use them.

Specifically, to take a current example, we should be sceptical about Aslef, the train drivers’ union, using its industrial muscle to secure a four-day week for its members on the London Underground. Its members are already well paid by Transport for London, which is generously subsidised by the taxpayer.

In other parts of the public sector, there is already a problem of the perception that public servants are allowed to work from home more than is strictly justified – a perk that is worth the equivalent of 8 per cent extra in pay, according to one study.

A four-day week is not exactly an obvious fit with Labour’s mission to increase economic growth. Ms Rayner should be careful not to undermine Rachel Reeves, the chancellor, as she tries to boost the wealth-generating private sector. Ms Reeves said in the election campaign that Labour ministers would be as careful with public money as if it were their own.

The deputy prime minister should tell local councils such as South Cambridgeshire that, while it is up to them to manage their own affairs, she would discourage them from appearing to privilege the public sector.