By Robert Cuffe

BBC Verify

A key crime measure routinely quoted by ministers excludes many crimes that affect women more often than men, the BBC can reveal.

The headline figure from the Office for National Statistics (ONS) shows "total" crime has halved since 2010 - but excludes sexual assault, even rape.

The ONS says it is more challenging to collect accurate data on these kinds of crimes.

But critics say the omission hides the extent of violence against women.

Hard to measure

Not all incidents are reported to the police, so the ONS surveys 30,000 randomly selected people in England and Wales each year to work out how many crimes actually take place.

The results of the latest survey will be published on Thursday.

It says it has to treat some crimes differently.

The ONS's Helen Ross said: "In face-to-face interviews, victims - most commonly women - can be unwilling to respond if their abuser is in the room or if their family is unaware of previous abuse."