Body cameras to be worn by London police officers
8 May 2014 Last updated at 07:49 BST
Scotland Yard is beginning what it says is the world's biggest ever pilot programme into the use of portable cameras worn by police.
A trial of the cameras will see 500 distributed to officers across 10 London boroughs. Firearm officers will also use them in their training.
Officers will store material from each incident and keep it on file for a month unless required for evidential purposes.
Matt Prodger reports.