The corruption uncovered by the police watchdog, the Independent Police Complaints Commission, is disturbing. Perverting the course of justice, abuse of authority, unauthorised disclosure, theft and fraud are all illustrated in its new report.

In defence of the police, it might be pointed out that of 8,542 allegations investigated over a three-year period, only 12 per cent were substantiated. Still, that is more than 1,000 cases. In only 47 was the evidence strong enough to pass to the Crown Prosecution Service. Some 18 officers were prosecuted, 13 found guilty and 10 sent to prison. That is a very small proportion. Some might therefore conclude, as the IPCC does, that corruption in our police forces is "not endemic". But others might raise questions about the efficacy of the IPCC.

The independent investigators have a smaller budget and fewer resources than many of the anti-corruption departments of individual police forces. It is an organisation which, until February, had gone an entire year without a chairperson. And it lacks the power to compel officers under investigation to speak. Some complainants allege that it is effectively a police-dominated organisation. Some police complain its investigations are protracted and inefficient. All of this has a seriously corrosive impact on the public trust essential to effective policing.

The chairman of the Home Affairs Select Committee, Keith Vaz, has, in response, announced the Committee will hold an inquiry into the IPCC – looking at the way it works and the difficulties it encounters in doing justice to both complainants and officers alike. The committee also needs to scrutinise the watchdog's relationship with the Crown Prosecution Service.

Among the measures it should consider are granting greater powers for the IPCC to conduct more effective investigations, making it obligatory for officers, civilian police staff, forces and third parties to co-operate more fully with its inquiries. The present set-up undermines police legitimacy and, on a practical level, the willingness of many in society to co-operate and give consent to our policing system.