Six Metropolitan Police officers have been accused of using “waterboarding”-the controversial torture technique-against four suspects in a drugs raid in north London last November.

The officers concerned have all been suspended and an investigation by the Independent Police Complaints Commission(IPPC) has been launched.

Police were said to have repeatedly pushed the heads of four suspects into buckets of water in an attempt to obtain information on the hidden drugs.

The technique, euphemistically described by the CIA as “enhanced interrogation”, has been widely used on Guantanamo Bay detainees but was outlawed in January by President Obama.

Through forced suffocation and inhalation of water, the practice can lead to permanent mental and physical damage or, if uninterrupted, death.

The torture allegations emerged from a corruption investigation into Enfield police accused of fabricating evidence and stealing suspects’ property.

The IPPC confirmed it was "investigating the conduct and actions of six police officers during the execution of two drugs warrants at addresses in November 2008".

It added: "During a Met investigation into allegations of the mishandling of property by the crime squad on Enfield Borough, watchdog officials were briefed regarding the actions of officers involved in the execution of this specific warrant.

"This is an ongoing criminal investigation and all six officers will be criminally interviewed under caution."

The claims come as Scotland Yard continues to investigate allegations that MI5 colluded with US agents in the torture of former Guanatanamo Bay detainee Binyam Mohamed

A Scotland Yard spokesman said: "The IPCC is independently investigating the actions of six officers during the arrests of five people in November 2008.

"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 allegations are likely to lead to greater pressure on the Metropolitian police commissioner Sir Paul Stephenson to revive trust in the police. Public concern is running high after alleged police brutality at the G20 protests.