The air ambulance was called after a collision involving a police van and a car in Bletchley's busy Sherwood Drive yesterday afternoon.
It is understood two people were injured and taken to hospital.
A witness said: There was aloud bang followed by a lot of police running about. A young child was in the car and at least two people were taken to hospital."
The collision happened shortly after 2.30pm and the road was blocked afterwards. A police spokesman said: "The road traffic collision involved a van and a car. The ambulance attended. No-one has been reported or arrested."