A major road in Hillingdon has been closed after a passenger in a car involved in a serious crash was found to have a suspected gunshot wound.
An air ambulance has been seen arriving at the scene on Uxbridge Road at the junction with West Drayton Road with one person having been seen lying on the ground.
Police have said they were called to the scene shortly before 3pm.
Buses have been diverted as emergency services respond to the incident.
An eye-witness said: “My aunt just saw the air ambulance landing in front of her car and we saw paramedics working on someone on the ground.
“They put the buses on diversion and there is a high emergency service presence.”
A police spokesman said: “A silver Mercedes was reported to have collided with a number of pedestrians and vehicles. None of the pedestrians are believed to have serious injuries.
“A male passenger in the Mercedes was found to be suffering from a suspected gunshot injury. The driver of the Mercedes stopped at the scene and is assisting police.”