Such is the extent of the overtime culture that permeates police forces, one officer is said to have claimed overtime while in the cells, after being arrested during his shift.

The officer, who works for a force in the north-west of England, arrived for work at 7am but was arrested for an unspecified offence at 11am. Due to the backlog of prisoners in the holding cells he was locked up for 10 hours at his own station before being questioned and eventually bailed shortly after 9pm. Noting that his shift was due to end six hours earlier, he claimed for the extra "work".

This tale is clearly extraordinary, but it illustrates just how attached to their overtime some officers are. Overtime should be used as a necessity. It is not an entitlement.

Our investigation has revealed that some officers in rural forces nearly double their annual salaries; others in the Metropolitan Police actually do so. While it is expected that those working extra hours in the public sector should be adequately remunerated, taxpayers are not being properly served if their policemen and women are working 70-hour weeks.

Obviously there will be police constables who put their hands up for every hour of overtime available, but these findings raise serious questions about mismanagement in those police departments issuing huge amounts of overtime.

There is also the issue of the public versus the private sector. Many employees of private companies are expected to work much longer hours than their contracts state with no overtime incentive whatsoever. The only reward in many jobs is the prospect of a day in lieu. Private sector workers would jump at the chance of trading these lieu days for a salary top-up of £25,000, but are not given the chance.

Last week this newspaper ran an article which told of the lack of detectives in police forces. It pointed out that officers want to stay in uniform rather than head to CID because of the better work/life balance – uniformed officers work four days on then have four off. These four days off allow officers time with their family, but also increase the potential for overtime.

Those making the most in overtime are also unlikely to go for promotion. Overtime is only available to PCs and sergeants. So why would a PC, making £62,000 a year after overtime, want to become an inspector, who makes £45,000 but cannot claim overtime?

A popular tactic among career constables and sergeants is to stay at a rank which allows overtime for the majority of their service and then "rank up" in their final years, to increase the size of their pension.