A THREE-CAR collision on the M4 caused long delays after a driver ploughed into the back of a police car on the hard shoulder.

The M4 Westbound was closed for an hour this morning and there was queueing traffic due to serious accident with three cars colliding between Junction 16 at west Swindon and Junction 17 at Chippenham.

The accident happened at around 10.30am, and the westbound carriageway was fully closed. The road has since reopened but is still restricted to one lane past the accident, near the Dauntsey overbridge.

An air ambulance has attended the scene along with fire crews and four people have been taken to Great Western Hospital with minor injuries. 

One constable from the Wiltshire Police Roads Policing Unit was medically trapped and had to be cut free by firefighters.

A spokesman for Wiltshire Police said: "Our unit pulled over a car for allegedly speeding on the M4. They stopped the car on the hard shoulder and another car has gone into the back of the police car.

"One of our officers was medically trapped in the car and was cut free before being taken to Great Western Hospital, along with the male driver of the other car and his daughter. 

"Everyone had minor injuries and have since been discharged from hospital.

"The road was fully reopened by noon but the vehicles have only just been recovered by 3pm while the Serious Collision Investigation Team were at the scene investigating."

A spokesman for South West Ambulance Service said: “A police car has pulled over another car to the hard shoulder when a vehicle approaching from behind has unfortunately gone into the back of it.

"This has meant there were three cars involved in the incident.

“There was nothing serious in terms of injuries. The air ambulance were called and two ambulances attended the scene.

“Four walking wounded were taken to First Great Western Hospital for checking over and patching up. They were conveyed to Swindon by ambulance at which point we left the scene.”

A spokesman for Wiltshire Fire and Rescue said: "We got the call at 10.44am and sent two appliances from Stratton and Westlea.

"One person was medically trapped and had to be cut free."