A seven-year-old boy has died after the car he was travelling in was in collision with a lorry.
The accident involving the silver Toyota Rav 4 and a blue DAF lorry happened on the A4146 Stoke Hammon bypass in Buckinghamshire at 2.17pm on Friday.
Fire crews and an air ambulance together with the ambulance service attended the scene.
A Thames Valley Police spokesman said: "Sadly a seven-year-old boy, who was a passenger in the car, died at the scene. Three people were taken to the John Radcliffe Hospital in Oxford where they were treated for serious injuries."
A 33-year-old man from Milton Keynes was arrested on suspicion of causing death by dangerous driving and has been released on bail while police continue their investigation which closed the road for several hours.
Pc Sandra Terry said: "This is a very sad case where a young boy has lost his life.
"We are in the process of investigating the circumstances which led to these tragic consequences and so would urge anyone who was in the area before this time and saw the incident itself or who had seen either vehicle prior to the collision to please contact us as a matter of urgency."
