Detectives are appealing for a man to come forward following a fatal collision in Hammersmith.
Police were called on Thursday, 24 December at 15:05hrs to a car that had collided with a motorcycle on Talgarth Road [westbound], W6.
The driver of the car is thought to have stopped briefly at the scene before driving away prior to the arrival of police.
The motorcycle rider, Martin Wall, aged 59 from Chelmsford, Essex was taken to hospital for treatment after suffering from a broken collar bone.
He was discharged from hospital but became unwell and subsequently died on Friday, 1 January.
Next of kin have been informed.
Officers are appealing for the man who was driving what is believed to be a BMW, to come forward and speak to them.
They are also asking any witnesses to the collision and anyone with dash cam footage to contact officers from the Serious Collision Investigation Unit on 020 8543 5157 or to call 101 and quote reference CAD3984/24Dec2020.