Former Metropolitan Police officer -- and Lib Dem mayoral candidate -- Brian Paddick has appeared at the Leveson Inquiry, and his witness statement contains an astonishing allegation against his ex-employers.

In a section about the Metropolitan Police Service's attempt to improve its image in the media, Paddick details the "negative commentary" on Ian Blair after he took over as Met commissioner. "The Met went from being very open to being almost paranoid," he writes.

One of the consequences of this, he adds, was that he was asked to "water-down" a report critical of the Met's handling of rape cases. Paragraph 19 reads:

Shortly after he became Commissioner, Sir Ian Blair asked me to review rape investigation in the MPS. Performance was patchy and he wanted the MPS to be the best in the world. The review revealed serious shortcomings and made strong recommendatons but senior officers were concerned about the impact the report would have on the MPS' reputation, particularly against the background of the criticisms levelled at the new Commissioner.

As a result I was told to tone down the criticisms and water-down the recommendations. My original report highlighted the changes over a period of four years, 2001/2 - 2004/5. It showed a large increase in the number of allegations of rape, but a similar fall in the percentage of allegations classified as rape by the police. It also identified wide variations in the way rape was investigated by the MPS within London.

The final report only analysed performance over two months in 2005 and sidestepped any criticism of the force, saying: "Any assessment of the performance of the MPS in the investigation of rape must be placed in the wider context of the complexity of rape allegations that are reported" and "without detailed case-by-case analysis, it's not possible to determine the extent to which police performance affected the outcome of the investigation."

In terms of remedial action, I recommended a radical change in approach, supporting a "consistent, victim-centred approach to the management of rape allegations". However, the final report concluded that existing practices were adequate, saying "it is adherence to best practice that needs to be addressed to ensure a consistently excellent service is delivered across London to the victims of rape."

[emphasis mine]

Paddick also claims that the Met's press officer told her that "her job was to ensure [the report] received no coverage at all". He concludes: "As a result, the service the MPS provided to rape victims was sacrificed in favour of the MPS' reputation."

If true, this is shocking. Campaigners have fought to bring attention to the low rates of conviction for rape, and the usual rejoinder is that there is no proof that cases are dismissed due to anything other than lack of evidence. The report outlined by Paddick would have provided useful statistics to challenge this, and help forces across London improve the way they dealt with victims.

Of course, this isn't the first time the Met's treatment of rape cases has been called into question. In 2010, an investigation by the Independent Police Complaints Commission found that three officers in the specialist Sapphire unit faked a victim's statement to make it appear as though she had retracted her allegation.

Earlier that year, one of the victims of serial rapist John Worboys told the Guardian that her allegations had been dismissed by the Met, allowing Worboys to continue his spree. (He was arrested, but officers believed his story that the victim was drunk.) "They talked down to me as if it was my fault, as if I was the criminal, and I just felt they didn't take me seriously," she said.

The Evening Standard report into the IPCC's investigation of the case put it like this: "The officer in charge had a "mindset" that a black cab driver could not commit such an offence ... the report describes a culture in which officers did not believe women if they made allegations of a sex assault after a night out."

If Paddick's claims are borne out, it seems that problems with some Met officers' attitudes to rape victims had been identified long before these two cases -- and the chance to address them was missed. All in the name of positive PR.

Thanks to our legal correspondent, David Allen Green, for bringing the evidence to my attention. I'm on Twitter: @helenlewis