Police officers accused of 'waterboarding' suspects

Six suspended after allegedly pushing suspects' heads into buckets of water

Six Metropolitan Police officers have been suspended over allegations of subjecting suspects to "waterboarding" – the CIA interrogation technique that simulates the experience of drowning – during a drugs raid in north London last November.

The claims are part of a leaked inquiry into alleged institutional corruption among officers in Enfield, which also includes accusations that police evidence was fabricated and suspects' property stolen. Senior police officers are most concerned by the claim that officers used the interrogation technique on four suspects during a raid on a series of properties in north London. They are understood to have pushed the suspects' heads into buckets of water in a bid to force them to reveal the locations of drugs.

A Scotland Yard spokesman said a police employee had raised concerns about the conduct of a small number of officers during an internal investigation into allegations of mishandling of property. He added: "Whilst the investigation is ongoing it is not appropriate to make assumptions. That said, these are serious allegations that do raise real concern. The Met does not tolerate conduct which falls below the standards that the public and the many outstanding Met officers and staff expect. Any allegations of such behaviour are treated very seriously, as this case illustrates, and if found true the strongest possible action will be taken."

The claims come at a time when Scotland Yard is investigating claims of waterboarding allegations made against MI5 by the British national former Guatanamo Bay detainee, Binyam Mohamed. It will also reignite public debate about police conduct that was ignited in wake of the hundreds of public complaints during the G20 protests.

Scotland Yard has referred the case of police brutality to the Independent Police Complaints Commission which is in the process of an "ongoing" investigation. In February, Scotland Yard said 10 police officers from the crime squad in Enfield were suspended and another two had been placed on restricted duties after an anti-corruption probe into the alleged mishandling of property. Eight – including the six as well as a detective sergeant – remain suspended and two remain on restricted duties.

Last night the IPCC confirmed that it was investigating "the conduct and actions of six police officers during the execution of two drug warrants at addressed in north London on 4 November 2008". A spokesman said: "During a proactive Metropolitan Police Service Directorate of Professional Standards investigation into allegations of mishandling of property by the crime squad in Enfield Borough which is being investigated by the IPCC, the IPCC was briefed regarding the actions of police officers executing the specific warrant. The case was referred to the IPCC on 3 April and on that date a decision was taken that a fully independent IPCC investigation would begin into these specific actions and conduct matters that are alleged to have taken place."