Britain's most senior police officer has admitted the way rape is investigated must be "drastically improved".
Announcing a review into the way rape claims are dealt with, Metropolitan Police Commissioner Sir Bernard Hogan-Howe said investigators are failing to treat victims with enough sensitivity and empathy.
"For a while, I've been concerned about how we, the police, approach and deal with sexual offences," he said today.
"There is some evidence we need to drastically improve how we deal with criminal investigations into rape."
More than 80 per cent of victims of sexual offences do not come forward - and of those who do, four in five are vulnerable because of factors such as drink, drugs of psychiatric illness, Sir Bernard said.
He added: "My concern has been whether or not the investigators are always as sensitive and empathetic to the victim's account, as they should be."
The Commissioner's comments came as it was announced that Dame Elis Angiolini, a former Lord Advocate of Scotland, will head a review into how sexual offences are dealt with by police. Her report is due to be published next February.
Director of Public Prosecutions, Alison Saunders, launching the review with Sir Bernard at Scotland Yard, said there had been some great strides over the last five to 10 years but there was a lot more to be done.
"We have seen an increase in the last few months of referrals coming through, but we need to improve the court process once the victim has decided to engage," she said.
Last month the Crown Prosecution Service (CPS) and the Bureau of Investigative Journalism revealed that there were 2,300 rape convictions in 2013, down from 2,433 in 2010, while 129 fewer rape suspects were convicted in 2013 than in 2012.
In the last year the number of completed prosecutions and convictions has increased, the CPS has said, but the conviction rate has dropped from 63.2 per cent in 2012-13 to 60.3 per cent in 2013-14.
Dame Elish said later in a statement issued by Scotland Yard: "The investigation and prosecution of rape presents uniquely challenging and sensitive issues. Overcoming these challenges requires appropriate policies, the highest levels of investigative skills and appropriate resources.
"Addressing the robust evidential requirements and any subsisting prejudice towards those who deserve the protection of the law also demands exceptional levels of preparation and advocacy. I hope this review will assist in the improvement of those processes."
Additional reporting by PA.
