Warning: this report contains distressing images.
Harrowing police custody footage has been played to an inquest into the death of a 39-year-old father in 2013.
Leon Briggs was suffering serious mental health problems when he was restrained by police in Luton then transported to a police cell by a firearms unit.
Channel 4 News applied to the Coroner to release the crucial video which shows the moments leading up to Mr Briggs’ death.