A Met police officer has been suspended over claims of racial abuse after he was secretly recorded by a Kurdish teenager he was arresting.
Scotland Yard said the officer is suspended
The boy used his mobile phone to record Pc David Yates, 26, allegedly making threats and swearing.
A West London Youth Court judge threw out a case against the boy after hearing the tape on 13 May.
Met Police chief Sir Ian Blair has condemned PC Yates' alleged behaviour as "outrageous".
The boy made the recording by activating his phone's record device as he was being put into a police van after his arrest in Paddington, west London in February.
A two-and-a-half minute tape of an exchange with Pc Yates, 26, a Territorial Support Group officer based at Paddington Green police station, was played to the court.
It is alleged that on it the officer swears repeatedly, accuses the boy of being a robber and rapist, and threatens to "smash your Arab face in".
District Judge David Simpson said the tape should be sent to the Met commissioner and the director of public prosecutions for them to consider disciplinary and criminal proceedings against the officer.
He told the court: "There's a lot of talk about respect and the lack of it. Respect is not something you get by putting on a uniform.
"I believe respect should be earned."
Sir Ian Blair, the Metropolitan Police Commissioner and Britain's most senior policeman, confirmed an investigation was under way into Pc Yates' alleged conduct and said he could be out of the force within weeks if found to be at fault.
He said he did not wish to prejudice the investigation but added: "On what I have read and heard, the behaviour alleged is outrageous.
"What I have asked for is that, if the evidence stacks up, then we will put the officer on a fast track procedure out of the force.
"On what I am hearing, that behaviour is totally contrary to the values of the Metropolitan Police and I do not need this man in the organisation."
The Independent Police Complaints Commission (IPCC) confirmed it will be investigating the claims.
IPCC Commissioner Deborah Glass said the group would not prejudge the outcome.
"Our investigators are meeting the Metropolitan Police Service... so they can get the evidence gathered so far," she said.
Scotland Yard has confirmed a 26-year-old constable has been suspended, pending an investigation into allegations of racial harassment.