Met Police officers wore tiny body cameras today for the launch of what is being described as the world's biggest ever pilot programme.
A total of 500 devices will be distributed to officers across 10 London boroughs. Firearm officers will also use them in their training.
The pilot scheme has been prompted following the death of Mark Duggan who was killed by Met officers at Tottenham station.
The death of the 29-year-old sparked the riots in the area that spread across England in August, 2011.
The Met has admitted if officers had been wearing cameras his death would have been easier to resolve.
Met Commissioner Sir Bernard Hogan-Howe 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.
Camden will be the first borough to trial the new cameras with further trials in Barnet, Bexley, Bromley, Brent, Croydon, Ealing, Havering, Hillingdon and Lewisham.
Footage of each incident will be kept on file for a month unless used for evidential purposes.
The cameras will be shared among the Met's 31,000 officers.