Firefighters cut a police officer free from a car after a crash in Colindale.
London Fire Brigade was called to Colindale Avenue shortly after 3pm after a collision between a car and a police car.
The driver of the police car was cut free and complained of back and neck pain.
He was taken by ambulance to a central London hospital. His injuries are not thought to be life-threatening.
A spokesman for the Metropolitan Police said the crash would be investigated by roads and transport officers.
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