By Marie Jackson
BBC News, London
Take a rape victim from south London and another from north London and the chances of their attacker being prosecuted could be heavily dependent on where they live.
The Met spends £3million a year on safe havens for victims
This "justice by postcode" scenario has proved to be of such concern to the Metropolitan Police that a review has been launched to examine the factors behind such varying clear-up rates.
Overall, figures show one in five reported rapes in London leads to a caution or charge, but the Met is keeping quiet on which boroughs are getting good results and which are falling behind.
The review, to be published by the end of July, also comes against a backdrop of falling rape conviction rates in the city.
Det Ch Insp Dave Osborn, who is working on the inquiry, said: "This review is not about the Met failing in rape (investigations) but about looking at good practice and making sure we are not complacent."
The Met's work on rape breaks down into three strands - investigation, victim care and cold case reviews of historic cases.
The review will focus on the investigation side and a look at what has allowed some boroughs to excel, said Det Ch Insp Osborn.
"It is about how we can find out what they do well so standards are consistent across London," he said.
In 2001, the Met launched Project Sapphire, billed as the most comprehensive reform programme on rape investigation ever undertaken by the service.
The project, which ran across all London boroughs, aimed to increase the Met's professionalism in the treatment of victims and the way rape allegations were investigated.
Sapphire also aimed to build public confidence in the police's handling of such crimes.
Its success, say police, has resulted in more people coming forward.
Sandra McNeill, from campaign group Truth About Rape group, welcomed the inquiry but was less convinced about its success.
"I get fed up with police saying that the number of rapes being reported is going up but not the number of rapes. More women are reporting rape because there is more rape."
"They rely too heavily on DNA. Police should be detectives. If she [the victim] said she screamed, why not ask the neighbours?" she said.
"In one case from London, officers said they had lost the evidence, which shows they just don't take it as seriously as they should."
But Det Ch Insp Osborn said: "We take rape very, very seriously. It's one of our core objectives.
"If one recognises that the vast majority of rape cases are committed by people known to each other, the issue is now over consent and how it's defined.
"DNA is, of course, important but it is used in a minority of cases."
He said teams of detectives made door-to-door inquiries, looked at CCTV and took witness statements.
Ms McNeill also said she was not convinced about standards of care.
"Victims of rape drop out at all stages because they are not being respected, supported or believed - it's very hard and humiliating.
"We know very few women lie about rape. They need to be given support so they don't withdraw at the first possible opportunity."
Det Ch Insp Osborn said London's three one-stop shop facilities called Havens in Camberwell, Paddington and Whitechapel offered a high standard of victim care.
The £1m-a-year units are recognised as world leaders in first class forensic gathering and evidence retrieval.
Victims who can self-refer or be referred by the police, are allocated a chaperone to support them through medical examinations (all conducted by females) to the conclusion of an investigation.
The Met's cold-case team, meanwhile, has been revisiting unsolved rape crimes from 1987 to 1995.
At the time, police had been unable to get forensic leads but advances in technology has now made new leads possible.
Essentially what Det Ch Insp Osborn wants is for its investigation strand to match the acclaimed victim care.
But he warned: "This is not in itself going to turn around a falling conviction rate - it would contribute but it won't be the only answer."
"It's much wider than policing investigation.
"It's about judges, juries, the Crown Prosecution Service, interpretation of the law and what rape is - as it's no longer the classic definition of stranger rape."