The Metropolitan Police was accused last night of shielding officers against accusations of rape after it emerged that dozens of complaints had not resulted in a single conviction over the past five years.

The figures, obtained by The Times, also show that since 2000 only 1 per cent of all public complaints of rape and sexual assault against Met staff were upheld by an internal police investigation.

Even then, a quarter of those who faced a disciplinary board were allowed to resign before any hearing and with police pension intact.

The disclosures are a big embarrassment to the Government, which is struggling to improve public confidence in how the police deal with rape and sexual assault victims. They are also a personal failing for Sir Ian Blair, the departing Metropolitan Police Commissioner, who came to the force as an expert on improving police performance on rape.

The figures were released under the Freedom of Information Act, but only after a five-month delay.

Last week it emerged that two women police constables, Julie Facey and Paula Church, are suing the Met for £1 million each over sexual assault and harassment allegations involving three male officers over two years.

The figures are the first instance of the Met providing evidence of its performance on tackling allegations of rape and sexual assault by its own employees. It comes after a promise last year by Assistant Commissioner John Yates to improve the national conviction rate of 5.7 per cent.

However, the figures show the conviction rate drops by half to just 2.8 per cent when the alleged rapist is investigated by colleagues in the Met.

Woman Against Rape, a campaigning group that provides support to victims, said that the figures illustrated why there should be impartial independent investigation of these types of cases. Lisa Longstaff, of the group, said: “They are proof of what rape victims have been saying: the police are protecting the rapist, particularly when the attacker is a police officer.”

Over the past nine years there have been 62 allegations of rape against Met officers and civilian staff by members of the public and their own colleagues, so-called blue-on-blue rape. Only four of these cases resulted in a successful prosecution. A fifth accused was not prosecuted, though an internal investigation found that there was a case to answer. Instead, he was allowed to resign before his misconduct hearing.

In 2003 there were nine reported alleged rapes, resulting in only two convictions.

Since then no one has been successfully prosecuted, although in 2006 there were 16 reported rapes, eight in 2007 and five last year.

When the victims of a rape or sexual assault are members of the public, the figures show their complaint is highly unlikely to be upheld by the Met’s Directorate of Professional Standards, the internal investigation unit known as ‘the Untouchables’.

Just four of the 311 public complaints in the last nine years were substantiated following an internal investigation. Nineteen of these were complaints of rape by a Met employee on a member of the public – but none were upheld.

A Met spokesman said: “Any instance where the conduct of our staff brings the Met into disrepute is treated extremely seriously.”

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