A BBC reporter has been released on bail after going undercover in a bid to investigate claims of institutional racism in the police force.
The BBC has defended the use of an undercover reporter to investigate the police
The journalist had been gathering material for a BBC documentary while working as a probationary constable for Greater Manchester Police.
The reporter, who was working in the force's Stockport Division, was arrested on Friday on suspicion of obtaining a pecuniary advantage by deception. He was released on bail on Saturday afternoon.
But the BBC has said any pay he had received had been kept in a separate account and was to be returned to the force at the end of the investigation.
The journalist, believed to be in his 20s, had undergone training and had been "operational", working as a probationary constable for about a month.
In doing so, Greater Manchester Police claimed he had broken an oath he had taken on joining the force and may have breached people's human rights.
Chief Constable Michael Todd said: "If true, we deplore this tactic, which would appear to be an outrageous waste of public funds used to train, equip and pay this individual.
"It has also deprived a genuine recruit of the opportunity to join the service."
A spokeswoman added: "Greater Manchester Police is accountable at all times to the public we serve and welcomes legitimate scrutiny.
"But this behaviour, if true, is reprehensible and only serves to undermine the work of the police service.
"The journalist is also in breach of an oath of attestation that he made in becoming a police constable as he has failed to act with integrity.
In condoning this act of unethical journalism, the media organisation may well have breached people's human rights."
But the BBC has defended the documentary makers' decision to put an undercover reporter through the police recruitment process.
A spokeswoman for the corporation said: "The BBC has spent several months investigating allegations of institutional racism within the Greater Manchester Police. We believe this to be a matter of significant public interest.
"We believed the only way to test the allegations was by a BBC journalist going undercover to be a part of the recruitment process, to see what happens when a recruit joins the force, is instructed at the training school, and is then placed on the force.
"That is the investigation that was under way. Monies paid by the police to our reporter have always been kept in a separate account and always with the intention of being returned to the Greater Manchester Police."