Image caption Operation Weeting is being run alongside two other investigations

Four journalists or former journalists at Mirror Group Newspapers have been arrested in London by police investigating alleged phone hacking.

It is the first time Scotland Yard has indicated it has identified a suspected plot to intercept telephone voicemails involving the newspaper group.

The inquiry centres on the Sunday Mirror between 2003 and 2004.

The four, who include ex-Sunday Mirror editor Tina Weaver and current People editor James Scott, were later bailed.

The Metropolitan Police said they have been asked to return to police stations on various dates in April.

Police working on Operation Weeting said three men, aged 40, 49 and 46, and a 47-year-old woman were held at separate addresses in south-east and south-west London at 06:00 GMT on suspicion of conspiracy to intercept telephone communications contrary to the Criminal Law Act 1997.

All are journalists or former journalists on Mirror Group Newspaper titles, they confirmed.

'Primary focus'

An email to staff from Simon Fox, the chief executive of parent company Trinity Mirror, confirms the names of four people arrested.

The email says another serving members of staff, Nick Buckley, the deputy Editor of the People and Mark Thomas, a former editor of the newspaper were also held.

All four are being provided with legal support, it added.

The People editor Mr Scott is also the former deputy editor of the Sunday Mirror while Ms Weaver is now an editorial member of the Press Complaints Commission.

All four are being interviewed at various police stations in London and searches are being carried out at a number of addresses.

They are yet to respond publicly to the allegations.

The Metropolitan Police said its officers would be "making contact with people they believe have been victims of the suspected voicemail interceptions" in due course.

In a statement it said: "Detectives on Operation Weeting have identified and are investigating a suspected conspiracy to intercept telephone voicemails at Mirror Group Newspapers...

"It is believed it mainly concerned the Sunday Mirror newspaper and at this stage the primary focus is on the years 2003 and 2004."

Police said the probe was separate to cases involving the News of the World, which closed down in 2011 in the wake of claims about phone hacking at the paper.

Police launched Operation Weeting in 2011. The investigation is running alongside Operation Elveden, a probe into illegal payments to public officials, and Operation Tuleta, which is an looking at computer hacking and other privacy breaches.