What does the word "rape" mean to you? For many reading this post, I suspect, it is a trigger to appalling events in their own lives. Because rape is an everyday crime. By my calculations, roughly 230 people are raped each day in England and Wales.

Police, this morning, called for specialist units to investigate rape allegations - senior officers are ashamed of a conviction rate they calculate at 6%. "Not good enough" says the Assistant Commissioner of the Metropolitan Police John Yates.

But analysis of the Home Office data on what they call "intimate violence" suggests the conviction rate is much lower. And the scale of the problem far greater. My source is the Home Office supplement to the British Crime Survey - Homicides, Firearm Offences and Intimate Violence 2006/07 (pdf link). This is a remarkable piece of research in which 13,000 people were asked to fill out an anonymous questionnaire on their experiences of domestic violence, sexual assault and rape.

It is an exercise that has been conducted three times now and is backed up by other academic studies. The results are consistent. One in 20 women said they had been raped since they were 16. One in 200 said they had been raped in the previous 12 months. In terms of the population of England and Wales, that suggests 85,000 women are raped each year - 230 a day. And yet the number of men convicted of rape is fewer than 800 a year. So the chance of a victim seeing her attacker jailed is less than one in 100.

But rape is a complex crime. Only 17% of rapists are strangers to their victim. Just 4% are cases of date rape. Half (54%) are committed by a husband, partner or ex-partner. What's more, even though their experience is technically rape in law, 57% of rape victims don't necessarily think of themselves that way.

To be clear what the figures categorise as rape, the definition is this: "the penetration of the vagina or anus without consent and penetration of the mouth by a penis without consent."

Since the 39,000 people who have taken part in the studies benefited nothing from alleging rape, and the results appear consistent, it seems probable that the research gives a realistic sense of the scale.

If one looks at the data on rape at any point during adult life, it suggests 700,000 women have suffered in that way - equivalent to the entire population of Leeds.

Figures for male rape are too small to measure on an annual basis, but the survey suggest there are approximately 80,000 men in England and Wales who have been raped in adulthood.

The data suggests, if anything, incidents of rape are going down slightly. But, to my mind, the numbers still paint a deeply troubling picture of sexual violence in the 21st century.

How should we respond? The police have made great strides in recent years to deal more effectively with allegations of rape. The idea of specialist units may help. But such is the scale of unwanted sexual advance, assault and rape revealed by the research, the answer surely cannot lie with policing alone.

