Police hope a pioneering rape investigation unit will lead to a significant improvement in conviction rates.

Operation Topaz, based in Bradford and Wakefield, became the first rape investigation unit in the country to take on an entire investigation from initial report to conclusion at court when it started last November.

West Yorkshire Crown Prosecution Service also established a rape and serious sexual offences unit, ensuring specialist investigators and lawyers had responsibility for all rape cases, to run alongside Topaz.

Detective Chief Inspector Marianne Huison, head of West Yorkshire Police’s child and public protection unit, who is in charge of Operation Topaz, said: “We are determined to improve our response to complaints of rape in an effort to ensure that offenders are brought to justice.

“It is early days and the first cases dealt with under the new regime are now proceeding to court. We hope we will be able to demonstrate a significant improvement in conviction rates over time.”

Det Chief Insp Huison was speaking after new research suggested Britain has the lowest rape conviction rates in Europe, at 6.5 per cent. The West Yorkshire figure is 6.6 per cent.

The policing standards watchdog, HM Inspectorate of Constabulary, is to ask victims why they feel they are being failed by the criminal justice system.

Det Chief Insp Huison said: “There are a number of reasons why the conviction rates for rape are so low, not least that the case will often rely on the strength of evidence given by the victim with little available evidence.

“Since the establishment of the rape investigation unit very favourable feedback has been received from support agencies about the improvement in the quality of service experienced by victims. Reporting rates for rape have increased by 15 per cent over the last 12 months which we feel demonstrates that victims have greater confidence in the police responding appropriately.”