Over the last few days the Guardian has reported that that, in the space of four years, there have been fifty six known cases where a police officer or other employee of the police service in England and Wales has been charged with or disciplined for sexual offences.

Fifty six sounds at the same time appallingly high, and relatively low. There are around 140,000 serving police officers in England and Wales, so this represents less than 0.1% of the police population, and an even smaller proportion if you include PCSOs, special constables, and civilian staff in the head-count. In light of this, it’s easy to believe the familiar rhetoric about a few bad apples: the police are only human, and some humans commit awful crimes.

But, as anyone who knows the first thing about rape will tell you, both the conviction rate and the reporting rate for rape and other forms of sexual assault are very, very low. The real scandal lies in the question that nobody seems to be asking: if there are fifty six cases that we know about, how many police staff are actually committing sexual offences?

Let’s accept, for the sake of argument, that the police are no more or less likely to commit a sexual offence than a member of the general public, and are no more or less likely to get away with it when they do. There are regional variations, but for England and Wales as a whole, around 6.5% of rape reports lead to a conviction. Now, not all of those fifty six police officers and staff were found guilty of rape or sexual assault: four are still awaiting trial, two committed suicide before a trial or disciplinary hearing took place, and several had been found guilty of other offences, such as sexual harassment, using police databases to obtain women’s personal information, or possessing indecent images of children, or inflicting unnecessary strip searches. These are still disgusting crimes, but they’re different types of crime so the same trends don’t necessarily apply.

This leaves thirty four men who were found to have committed rape, sexual assault, or abused their position to coerce vulnerable women and children into sex, with at least seventy two individual victims (in some cases the number of complainants wasn’t clear from the information available, i.e. someone convicted of two counts of rape may have raped two different people, or one person twice). If the 6.5% conviction rate applies, then it would mean that 1108 people reported having been sexually assaulted.

And reported assaults are only the tip of the iceberg. It’s difficult to put an exact figure on unreported crimes, but a lot of estimates suggests that fewer than 10% of rapes are reported to the police. If reporting rates are at 10%, then that would mean that almost ten thousand incidences of rape or sexual assault were never reported; if, as some estimates suggest, only 5% are reported, then over twenty one thousand offences weren’t reported.

The real scandal here is not that fifty or so police officers and staff have been caught committing sexual offences, but that there are potentially thousands who are committing those same offences and not being caught.