Women who report a rape are five times less likely to see their attacker convicted in some parts of the country than in others, according to new research.

An analysis of official figures reveals that the conviction rate for rapists fell in 18 out of 43 police force areas in England and Wales between 2004 and 2006.

In Leicestershire, fewer than one in 35 women who report a rape see a successful prosecution, but in Cleveland that figure improves to one in seven.

The number of convictions is below 10% in most regions.

Campaigners blame inherent faults in the criminal justice system. They say in some cases police fail to take rape victims seriously.

A quarter of reported rapes in the UK are not treated as a crime and are never pursued.

“It is a national scandal that thousands of victims of rape have no access to justice,” said Katherine Rake, director of the Fawcett Society, which compiled the research.

“In many cases women face a culture of disbelief, and delayed responses lead to the loss of vital evidence.

“These disturbing figures reveal that women face a postcode lottery when reporting rape to the police.” Vera Baird, the solicitor-general, said she was worried by the low conviction rates and would speak to chief crown prosecutors in the worst-performing areas.

The research is based on the latest figures for court proceedings and crime data from the Home Office and Ministry of Justice.

In 2004, there were 13,272 reported rapes in England and Wales. In 2006, the figure rose to 14,449.

In Cambridgeshire, Bedfordshire, Dyfed Powys, Sussex and Leicestershire only 3% of reported rapes ended in conviction in 2006.

By contrast, Cleveland, which has a specialist support centre for rape victims, saw a 13% conviction rate.

In South Wales successful prosecutions fell from 12.2% in 2004 to 5.9% in 2006.

In Gloucestershire, where fewer than 1% of reported rapes led to convictions in 2004, the success rate increased to 7.4% by 2006.

“We have begun to turn things around by working to collect better evidence early,” said Det Supt Geoffrey Brookes of Gloucestershire police.

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