Police say there is still more to be done to improve the investigating of rape
Rape claims are being left off official crime records, the BBC has learned.
Figures obtained following a Freedom of Information request showed some UK police forces were failing to record more than 40% of cases.
Rules state only allegations verified as false, reported to the wrong force, or recorded in error can be removed.
The Association of Chief Police Officers said advances had been made in rape investigation but campaigners said women were being denied justice.
The figures showed wide regional variations but some forces had such a high number of cases removed from records - known as "no-criming" - that critics said it was evident the rules were not being properly applied.
Cause for concern
In Northumbria, there were 382 reports of rape. Of those, 172 never made it into official Home Office figures and that was before any were "no-crimed".
Police in Durham said only five of 130 cases had been "no-crimed" yet the figures showed a further 83 cases were never officially recorded in the first place.
In contrast, forces in Humberside, Gloucestershire, and Northamptonshire recorded at least 90% of cases for investigation.
Northern Constabulary, which covers the Highlands, Western Isles and Orkney and Shetland, puts every case on its records.
HM Inspectorate of Constabulary demanded improvements in recording rape claims two years ago but has admitted there is still cause for concern.
Lisa Longstaff and rape victim Claire Thomas on how claims are handled
The figures also showed hundreds of complaints lodged in the year to March 2008 never went forward to a full investigation.
The Association of Chief Police Officers (Acpo) said significant advances had recently been made into investigating rapes but admitted there was still much more to do.
Chief constable of Cheshire Police, Dave Whatton, who speaks for Acpo on rape issues, said even when allegations were withdrawn they must still be investigated.
"If somebody's saying, 'I have been raped but I'm not prepared to go forward with this at court,' then it should still stay as a crime.
"That isn't something that should be withdrawn. Because in terms of threshold tests, it has to be proved that the offence did not take place, not that we can't take forward the investigation."
Lisa Longstaff, of campaign group Women Against Rape, accused police of not taking rape seriously enough.
She said police have 72 hours in which to investigate a rape allegation and declare it a crime but some were using this as a way to avoid investigating.
BBC website readers have been commenting on this story. Here is a selection of their thoughts and experiences.
I was attacked by two men two years ago and reported it the morning after. I was accused by a female officer of making it up and being 'a fantasist' because I had been drinking. I have talked to police officers who say they know that the CPS will not prosecute most of the cases they investigate, so they feel there is little point in spending resources on an investigation. The process has got to change. Ursula, UK
'Drink', 'provocative clothing', 'walking alone' and 'on a date with': if these words were ever associated with a victim of male or child rape not getting justice there would be a public outcry. Yet all these have sometimes been used as excuses for women perceived to be 'asking' to be raped. The prejudice based on sensationalistic coverage of those few false rape cases also seems to be all too readily at the forefront of some people's minds when a rape is reported, rather than the suffering of the victims. Alison, North Wales, UK
I think the media should improve how they report rape claims instead of the knee jerk assumption that an allegation of rape is as good as a guilty verdict. The fact that so few allegations result in convictions can have two interpretations: first that rapists are getting away with it - which is quite possible; second that those who claim they are victims are making false allegations, which is also possible. For what it is worth, I have no idea what percentage of alleged rapists is actually guilty, whether it be all or none. I doubt the BBC knows any better. Steve, London, UK
I am a victim of rape in a different way: I was accused of rape when I had blatantly not done a thing wrong. After tests, the girl was cautioned for wasting hours of expensive police time and I was let go. The whole thing was very hurtful and my dad wanted to sue for slander. I am appalled by the fact that women think they will get away with this. I'm not surprised at the numbers provided by your recent investigation. Anonymous, UK
I work for an independent rape and sexual abuse organisation. Many of my clients are openly discouraged from pursuing prosecutions and some have had their allegations disbelieved. It is not the job of the police to tell someone that court will be tough for them and they probably shouldn't take things further. Unfortunately, the targets they are set and the amount of cost and paperwork mean that many police make quick judgments. The number-crunching process dictated by the government causes more of a skew on figures than anything else. Anonymous, North West, UK
It's fairly clear that the police force suffers from the same problem many other public institutions have nowadays - league tables and obsessions with statistics. This encourages them to shy away from crimes such as rape, which are difficult to handle and harder to prove. Rosie, London, UK
The way justice systems deal with sex crimes is generally contemptible across the world but one would have expected rather better from the UK. Such situations are the product of inaction on the part of the public: the rapist may the one ultimately responsible for the act but society is responsible for the administration of justice thereafter. Demand action, petition your MP. Ross White-Chinnery, Beijing, China
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