Police were called at 9.20am on 6 August to reports of a collision between a lorry and a pedestrian on Park Lane.
The victim, believed to be aged in his 50s, was pronounced dead at the scene at 9.27am.
Despite extensive efforts, officers have not been able to identify the deceased. They are now releasing an image of the man walking in Park Lane moments before the collision.
Detective Sergeant Andy Russell, from the Roads and Transport Policing Command, said: “We urgently need to find out the identity of this man, so that his family can be informed of his death.
“Please do call police if you know his identity or if you think you recognise him and can provide us with any information.”
Anyone with information is asked to call the Serious Collision Incident Unit on 020 8543 5157.
The driver of the lorry stopped at the scene and is helping police with their investigation. There have been no arrests.