'I fell asleep while driving a tram'
Four drivers have admitted falling asleep while in control of a tram on the Croydon line, an investigation for the BBC Victoria Derbyshire programme has found.
Seven people died on the line after a tram derailed last year.
Drivers say a safety device, designed to stop the tram if they suddenly become incapacitated, did not work.
There is no suggestion a problem with this device was responsible for the derailment.