A police officer has suffered a "potentially life-changing" leg injury after he was hit by a car he attempted to stop in Hillingdon, London.
The officer was on a routine patrol when he attempted to stop a silver Vauxhall Corsa.
As the officer moved towards the car to speak to the occupant, it accelerated into him and sped off.
The man suffered a leg injury and was taken to hospital by ambulance.
The Metropolitan Police said the injury has been assessed as potentially life-changing.
The incident happened at around 6pm on Friday in Manor Waye, Hillingdon, north-west London.
Chief Superintendent Peter Gardner, who is responsible for policing in west London, said described what happened as "shocking" and said it "was a deliberate act to evade police which has left one of my officers in hospital.
"My thoughts are with my injured colleague and his family as we await an update on his condition.
“I want to be clear that incidents like this are totally unacceptable and detectives will be thoroughly investigating in order to bring those responsible to justice.
"We have already begun the process of collecting dash cam footage from drivers who were in the immediate area at the time but every piece of evidence is crucial.
"I would also ask anyone who was in and around Manor Waye at the time of the incident to check any dash cam or doorbell footage they may have to see if it captured what took place.”
Anyone with any information about this incident is asked to call police on 101 or tweet @MetCC, providing the reference CAD 6047/21MAY.
Alternatively, anonymous information can be given to the independent charity Crimestoppers on 0800 555 111.