About 1,000 police officers are hitting high streets across London in a bid to cut mobile phone robberies.
Met officers will be urging people to keep mobile phones out of sight
It is the Metropolitan Police's latest move in its "Safer Streets" initiative, which was first introduced in 2001.
The Met says the operation has already cut street crime by about 30% - 5,000 offences are now reported each months.
Volunteer officers will be out in 23 boroughs across the city offering a property marking service and advice about keeping mobiles safe.
'Out of sight'
The members of the Special Constabulary, Volunteer Cadet Corps, and Volunteers in Policing will be in uniform either in town centres, or patrolling shopping areas, or at the front counters of police stations.
It follows the Met's "Out of sight is safer" poster campaign in September which also targeted mobile phone users.
The force says about 50% of all street crime involves mobile phones and has urged people to keep them out of sight around crime hot spots such as Tube stations.
At the time, Assistant Commissioner Tim Godwin said: "The message is simple: 'Keep valuables out of sight whenever possible'.
"When you do have to take your phone or cash out in a public place, be aware of who is around you. Street robbers tend to be opportunistic, so don't make yourself an easy target."