One of the men arrested in the raid at the centre of the police waterboarding inquiry was later charged with assaulting a policeman, it emerged yesterday.

All charges against Bernasko Adji were later dropped as claims of theft, evidence fabrication and torture were disclosed in an anti-corruption investigation into officers based at Edmonton police station in North London.

The Times revealed yesterday that torture allegations against six Metropolitan Police officers are being investigated by the Independent Police Complaints Commission. The investigation has already led to the collapse of a drugs trial, the suspension of several officers and an overhaul of the command team in the borough of Enfield.

There are concerns that the waterboarding claims could also lead to a series of appeals against convictions obtained by officers based there. Mr Adji, 36, was one of five people detained by police in drugs raids in North London in November last year. Three of those arrested — Mr Adji, Nanyere Nwankwo, 24, and Ajah Mpakaboari, 33 — are alleged to have been victims of police brutality. All three are understood to be African immigrants, which adds an element of potential racism to an already complex and sensitive inquiry.

The two others arrested in the raids — Nicholas Oforka, 25, and his partner Victoria Seabrook, 24 — were detained at a separate address. They have made no allegations of ill-treatment. Shenel Johnson, Miss Seabrook’s solicitor, said yesterday that her client was five months pregnant when police raided her home searching for cannabis.

“Victoria was not physically harmed but she was in her pyjamas when the police came in — she had to get undressed and change her clothes with three male officers in the room,” said Ms Johnson, of SJ Law.

“Mr Nwankwo, who she knew as David, told her that after the arrest the police were kicking him and put his head down a toilet and repeatedly flushed it. He also had a cut on his hand when he got to custody. She also heard Ajah Mpakaboari had blood on his clothing when he got to the police station.”

Miss Seabrook reported the loss of some items of property which she says went missing during the police raid.

The commission said that its inquiry was continuing and that all six officers will be interviewed under caution.

Some sources have suggested that the allegations point to the activities of rogue officers rather than systematic torture.

It is understood that the allegation of “waterboarding” was first uncovered by the Met’s own anti-corruption inquiry, which involved covert operations at Edmonton police station, and that the word is included in the official document in which Scotland Yard referred the inquiry to the IPCC.

The torture allegations have come to light at a time of mounting concerns over public confidence in policing.

Complaints about the Metropolitan Police have almost doubled from 4,455 in 2003-04 to 8,849 in 2007-08.

Across England and Wales complaints against police forces went up from 15,885 in 2003-04 to 28,963 in 2004-05.

Chris Huhne, the Liberal Democrat home affairs spokesman, said: “The image of the police and the Met in particular has been tarnished by the G20 protests and the allegations of waterboarding. The huge rise in complaints in recent years is worrying evidence of a developing ‘them and us’ culture. It is also suggestive of a growing culture of indiscipline in the force.”

Boris Johnson, the Mayor of London and Metropolitan Police Authority chairman, said that the waterboarding allegations were extremely serious. He added: “I am certain Sir Paul Stephenson [the Met Commissioner] will take the strongest possible action to deal with any allegations of misconduct.”

Jenny Jones, a Green Party London Assembly member, said: “If these accusations are substantiated then serious disciplinary action must be taken. The police should be a public protector, not an organisation that uses criminal torture tactics.”

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