A police video shows officers chasing the car and smashing a window with a baton Police video

A 70-year-old stopped because he was not wearing a seatbelt ended up co-starring in a scene worthy of the cop drama parody Hot Fuzz, with police in a quiet country lane forcibly stopping his Range Rover after a 30mph chase, leaping on to the bonnet and smashing a window before dragging him from the driver's seat.

The police video shows the chase, with sirens blaring as police and suspect drive neatly along pretty country roads, keeping well in to the correct side of the road and within the speed limit. At one point a police voice is heard calmly saying: "No change, no change, four zero or 30 miles an hour, still on the right side of the road, quite happy to continue."

The scene changes dramatically when the Range Rover is stopped, apparently by a stinger device laid across the road by police from another unit, who also flag down the car on foot.

Immediately, one policeman leaps from the following car, runs to the Range Rover and tries to smash the window with a baton, while a man from the other unit leaps on to the bonnet and a voice from inside the car can faintly be heard repeating: "Get off, get off!" A passing motorist stops to see what is happening but is ordered back into his car by the police. Eventually the pensioner is dragged by the arm out of his car.

The drama began when Robert Clive Whatley, a retired businessman from Usk who has suffered a stroke and takes medication for a heart condition, was challenged by Gwent police in Cwmbran for not wearing a seatbelt.

He drove off as the police were issuing a fixed penalty notice, and later told Caerphilly magistrates court that he thought the police were finished with him and he needed his medication. When he realised he was being followed by a patrol car with flashing blue lights and sirens, he thought they were giving him a police escort home, he told the court.

"My survival instinct was such was that I was trying to assist the officer the best I could. I feared another stroke. I thought he had finished with me. I just drove off coolly and calmly and not off at speed."

The police claimed it was Whatley who had behaved aggressively.

He was found guilty of not wearing a seatbelt, of failing to stop for a police officer and of having tinted car windows that did not conform to legal requirements. He was cleared of failing to stop after an accident, and admitted having a non-regulation registration plate. He was fined a total of £235 and ordered to pay £300 towards prosecution costs.

He has made a formal complaint to Gwent police, who expressed "great concern" over the reports. Two officers have been suspended, and the Independent Police Complaints Commission is investigating the incident.

• This article was amended on 11 August 2010. The original referred to Cymbran. This has been corrected.