Victims of sex crimes under the influence of alcohol can provide accounts "just as accurate" as those that are sober, a study has found, reigniting calls for police to change the way they deal with rape victims.
Researchers examined the influence of alcohol on a women's ability to remember a sex attack by quizzing them about an "interactive hypothetical" scenario 24 hours and four months after it had occurred. The study was undertaken to challenge the "misconception that intoxicated victims and witnesses are unreliable".
Dr Heather Flowe, who led the study, said alcohol consumption heavily impacts the way crime victims are dealt with: “When a victim is intoxicated during the crime, questions about the accuracy of testimony are raised in the minds of criminal investigators. Out of these concerns, the police might forgo interviewing victims who were intoxicated during the offence.
"On the other hand, almost always in sexual offences, the victim is the only one who can provide information about the crime to investigators."
The University of Leicester study found that while intoxicated participants reported fewer pieces of information - than those who were sober - the accuracy of what was recalled "did not differ". It concluded: "Intoxicated participants could accurately retain information from the event as well as those who were sober".
Detective Inspector Reme Gibson from Leicestershire Police’s Rape Investigation Unit said: “It has been a long held misconception that victims and witnesses who are intoxicated are not able to give as good an account as they would when they are sober.
"The delays in speaking with victims accounts sometimes for loss of potential evidence, although alcohol is not the only factor that would influence whether or not an officer would interview a victim."
He said working with the research team was a "huge benefit to our understanding of the effects alcohol has on memory".
The research, one of the first to use a placebo controlled trial to investigate the effects of alcohol on memory within the context of a sexual assault, is being used to help develop National Guidelines for how the police should interview sexual assault victims. The researchers are working with the Crown Prosecution Service and Leicestershire Police.
Inspector Gibson said: “I hope these findings better support future investigations, particularly in the sexual violence arena which is already often complex and not without challenges.”
During the study researchers gave 88 women either a high or low dose of alcohol - vodka and tonic water, or just tonic water - before they went through a computer simulation of a sexual encounter, which they could leave at any time. If they remained until it was completed, it ended with consensual sex.
If participants tried to leave at any stage they were met with what researchers said was "a sub-scenario, which describes a legally definable act of rape". They were then given a multiple-choice memory test on what had taken place.
Dr Heather Flowe explained that "serious violent offenses" often involved intoxicated witnesses and victims, especially sexual assaults and rapes, where both the victim and perpetrator "are likely" to have been under the influence of alcohol.
She said given crimes are "more likely" to be solved with victim testimony researchers wanted to know what affect alcohol had on victims' memory and when they would report the crime.
"We wondered whether intoxicated victims take their mental state during the crime into account when rendering their testimony to investigators. If they take into account that their memory has been impaired by alcohol, they should report information only when they believe it is likely to be accurate.
“Accordingly, intoxicated victims should report less information overall, but the accuracy of the information they do report might not be different from sober victims.”
The study comes after new guidance were issued to all police forces and prosecutors as part of a "toolkit" to move rape investigations into the 21st century.
Under the rules men accused of date rape will need to convince police that a woman consented to sex.
The Director of Public Prosecutions, Alison Saunders, said in January that it was time for the legal system to move beyond the concept of “no means no” to recognise situations where women may have been unable to give consent.
She said rape victims should no longer be “blamed” by society if they are too drunk to consent to sex, or if they don't object because they are too scared of their attacker.
Under the rules police and prosecutors must now put a greater onus on rape suspects to demonstrate how the complainant had consented “with full capacity and freedom to do so”.
Campaigners described the move as “a huge step forward” in ensuring fewer rapists escape justice.
Mrs Saunders said: “For too long society has blamed rape victims for confusing the issue of consent - by drinking or dressing provocatively for example - but it is not they who are confused, it is society itself and we must challenge that.
“Consent to sexual activity is not a grey area - in law it is clearly defined and must be given fully and freely.
“It is not a crime to drink, but it is a crime for a rapist to target someone who is no longer capable of consenting to sex though drink."