Image copyright Reuters

Three Met Police police officers quizzed over claims they exchanged porn on mobile phones will not face criminal charges, Scotland Yard says.

The three constables were arrested on 19 December.

The officers are from the Diplomatic Protection Group, which guards foreign embassies and controls access to New Scotland Yard and Downing Street.

A fourth officer from the same unit was also interviewed on 8 January in connection with the investigation.

The officers, who are all male, allegedly sent each other picture messages using phones, and the Met said the images were "extreme" but did not involve children.

All the officers remain subject to an investigation into allegations of misconduct.

After their arrest, the three constables were questioned at a central London police station and search warrants were executed at their home addresses.

Of the three officers who will face no further action, one was suspended and the other two were put on restricted duties while the case was investigated.

'On hold'

In an earlier statement, the Met said it had "voluntarily referred the matter" to the Independent Police Complaints Commission, which had said it should be "investigated locally" by professional standards officers.

A file was sent to the Crown Prosecution Service and the professional standards misconduct investigation was put "on hold" pending its decision.

One of the four officers was already on restricted duties due to Operation Alice, the investigation into police conduct in the "plebgate" row.

That arose from an incident in which MP Andrew Mitchell, then chief whip, was accused of calling Downing Street police officers "plebs", which he denies.

The Met said the arrests over pornographic images were not linked to Operation Alice in any way, but came about following inquiries made as a result of that investigation.