Landmark changes to operational policing will be trialled from today in an attempt to boost transparency and accelerate convictions.
Officers with the Metropolitan Police will begin wearing tiny cameras on their uniform, designed to capture evidence at scenes of crime and help support prosecution cases.
The trial, thought to be the largest in the world, will see a total of 500 cameras distributed to 10 London boroughs. Firearms officers will also be testing the cameras in their training environment with a view to wearing them if the pilot is successful.
It follows criticism of the Met following the death 29-year-old Mark Duggan at the hands of armed officers, which sparked the 2011 riots.
Met commissioner Sir Bernard Hogan-Howe said the cameras would result in speedier justice for victims, particularly in cases of domestic violence.
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 debate over the more widespread use of body-worn cameras by British police comes after a jury at the inquest into Duggan's death concluded in January that he had been lawfully killed after being shot dead by Met marksmen - a conclusion which prompted outrage from his family and supporters.
None of the officers involved in the incident in London were wearing body cameras.
The Met has continued its efforts to repair the damage to its relationship with the community caused by the controversial shooting.
Speaking ahead of the pilot, the Met said officers taking part in the pilot must comply with guidelines about when cameras are to be used, but that they will not be permanently switched on.
Camden Borough is the first to take delivery of the new cameras, from today, with further trials in Barnet, Bexley, Bromley, Brent, Croydon, Ealing, Havering, Hillingdon and Lewisham.
Officers will store material from each incident and keep it on file for a month unless required for evidential purposes.
Sir Bernard said the cameras could have helped in the Duggan case.
He told BBC Breakfast: "I think as we saw in the recent incident - fairly recent incident - regarding Mark Duggan, there was a great dispute about what Mark Duggan was holding at the time he was shot, and this hopefully would have helped to resolve that."
If officers are found to regularly fail to switch on their cameras when they should do it will be treated as a disciplinary offence, he added.
He said the cameras would "capture the reality of some of the horrible things we have to deal with from time to time".