Mr Lentell, the ward councillor for Over and Willingham, said he was “massively in favour” of four-day weeks in principle, but thought the trial was “horrifically unfair”.

He said: “Ratepayers are mightily cheesed off that they are subsidising council staff.”

Mr Lentell’s motion, external, which is being discussed by councillors on 14 January, does not call for a ban on second jobs, but asks the council to introduce “appropriate monitoring and reporting mechanisms”.

The motion said there should be “clear guidelines” prohibiting staff from doing other jobs during their paid day off that “could conflict with council duties or undermine public trust”.

It also called for an “unequivocal prohibition” on staff using time freed up by the trial to sell their services back to the council.

Research suggested that second jobs were relatively common, with a Royal London survey of 4,000 workers carried out in 2022 stating that 16% of adults in the UK had one.

A further study by SCDC of employees at its Waterbeach waste depot found that of 170 employees surveyed, all of those with second jobs said they had one before the four-day trial.