Detectives are appealing for information and witnesses following a collision in Haringey.
Police were called at 07:55hrs on Saturday, 28 May, to reports of a collision in Great Cambridge Road at the junction with White Hart Lane, N17.
Officers and the London Fire Brigade attended and found two passengers - a 28-year-old man and a 29-year-old man - with injuries trapped inside a Vauxhall Astra.
The London Ambulance Service (LAS) were already on scene prior to police arrival after a passing ambulance was flagged down by members of the public.
The 28-year-old man was taken to an east London hospital where he remains with life changing injuries. The 29-year-old man was taken to a north London hospital with injuries not thought to be life threatening or life changing.
Detectives for the Serious Collision Investigation Unit are investigating.
At this early stage officers believe that the Vauxhall Astra was in collision with a stationary van, it then mounted the pavement and collided with a tree.
Members of the public went to the assistance of those trapped inside the car and it is believed the driver of the vehicle then fled the scene prior to the arrival of police. Enquires are underway to trace him.
Detective Constable Charlie Pulling said: "This is a busy area and there were a number of other road users who were in the vicinity at the time of the incident. I am appealing to anyone who may have seen the collision or the events leading up to it, to please come forward and assist us with our enquires.
"We believe that there were three people in the vehicle at the time of the collision and it appears that the driver is still outstanding. We are unsure whether or not he sustained any injuries and it is of paramount importance that we trace him immediately."
Anyone who witnessed the collision or has any information is asked to contact the Serious Collision Investigation Unit at Alperton on 020 8991 9555 or Crimestoppers anonymously on 0800 555 111.