An air ambulance landed in Trafalgar Square after an unmarked police car was involved in a crash in central London.
The police car collided with another vehicle on The Mall on Monday afternoon.
Paramedics and firefighters also rushed to the scene at about 2pm.
Video footage and photos posted on social media showed the air ambulance land in the busy square in the heart of the capital.
Scotland Yard said the driver of the police car was rushed to hospital. His injuries are not believed to be life threatening.
The other three occupants of the car were treated at the scene but were not taken to hospital.
The driver of the other car was not injured.
