Police and motorists were involved in a terrifying hour-long stand-off with a dangerous dog, writes Tim Hughes.

The 20-month-old English bull terrier, described as 'uncontrollable' by its owner, caused chaos after escaping on to a busy roundabout and then jumping into a car.

The dog, named Thor, was receiving treatment to control its aggression at the Canine Training and Rescue Centre at Weston-on-the-Green, near Bicester.

Owner William Walker had locked it in a van in the Sainsbury car park at Kidlington while he was at work in the supermarket. The animal is thought to have escaped through an open window before going on the rampage.

A couple who saw the dog on the Kidlington roundabout early on Saturday morning stopped to rescue it, but found themselves trapped when it leapt into their car.

They called the police, but two officers sent to the scene were unable to remove the dog.

Thor was eventually subdued and dragged from the car by Thames Valley Police's animal welfare officer Albert Honey. It was taken to private kennels before being reunited with Mr Walker. Mr Honey accused Mr Walker of acting irresponsibly by keeping the dog in a public place. He said: "I find it incredible that such a strong, powerful and aggressive dog should be left in a van in a supermarket car park.

"A dog such as Thor should never be left unattended.

"It was a dangerous incident and people were at risk of being bitten. The dog terrified the motorists and the police officers. A van is no place to keep a dog."

Mr Walker denied that he had acted irresponsibly and insisted that the dog had been stolen from the van. He said Thor was uncontrollable because he suffered from a rare meat allergy, but was in the process of being retrained as a family pet.

He said: "Thor is an extremely aggressive and anti-social animal. It's not against the law to keep him in the van. He had had plenty of exercise and was sleeping. It was safer than keeping him at home."