Barnet police will be among the first to wear cameras fitted to their uniforms as part of a trial organised by the Metropolitan Police Service.
A total of 500 cameras will be distributed to ten London boroughs chosen to take part in the pilot.
Two response teams in each borough will wear the cameras as they answer 999 calls during the year-long pilot.
The findings will be evaluated by the Mayor's Office for Policing And Crime (MOPAC) and the College of Policing before any decision about a future roll-out is made.
The MPS has said the cameras have already helped improve evidence during smaller scale trials, and Commissioner Sir Bernard Hogan-Howe has predicted they will also bring speedier justice for victims, especially in domestic abuse cases.
He said: “Body-worn video will not only help us fight crime and support victims but help the Met to be more accountable.
“Our experience of using cameras already shows that people are more likely to plead guilty when they know we have captured the incident. That speeds up justice, puts offenders behind bars more quickly and protects potential victims.
“Video captures events in a way that can’t be represented on paper in the same detail and it has been shown the mere presence of this type of video can often defuse potentially violent situations without the need for force to be used.
“I believe it will also show our officers at their best, dealing with difficult and dangerous situations every day but it will also provide clearer evidence when it’s been alleged that we got things wrong. That has to be in both our own and the public’s interest.”
The MPS said the cameras will not be permanently switched on but members of the public would be informed “as soon as practical” that they are being recorded.
The camera will be attached to the officer’s body armour and at the end of each shift they will upload the material to a cloud-based server.
The images will be deleted after 31 days unless required for evidence.