Body-worn cameras will help "to get better convictions" because the filmed evidence against them will be robust, the head of the Metropolitan Police told Good Morning Britain.
Bernard Hogan-Howe said some evidence was "really hard to capture" with a written statement and providing film would help the victims of crime.
"Secondly, it helps to get better convictions because it is such compelling evidence and quicker because often people will plead guilty when they know that sort of evidence is against them."
The Borough of Camden will be the first to take delivery of the new "body-worn-video" cameras, with further trials in:
Officers will store material from each incident and keep it on file for a month, unless it is required for the purposes of evidence.
Metropolitan Police Commissioner Sir Bernard Hogan-Howe said the body-worn video cameras being trialled would result in speedier justice for victims and help the force be "more accountable".
The commissioner said: "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."
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 wear tiny cameras attached to their uniform, designed to capture evidence at scenes of crime and help support prosecution cases.
A total of 500 cameras will be distributed to 10 London boroughs during the trial, which is thought to be the largest in the world.
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.