A witness has described the dramatic moment police swarmed the White Hart Roundabout because of suspected attempted escape from a prison van. 

A man in his 20s was being transported in a Serco prison van for an appearance at Swindon Magistrates Court on Tuesday morning, police said, when he attempted to escape.

The force said that he began to hurt himself en route, forcing the van to stop at the busy junction, where he assaulted and hospitalised one of the guards before attacking two police officers.

"It was crazy, all of a sudden there were police cars everywhere, I think I remember counting at least eight but there were probably more," a witness, who did not want to be named, said.

"I didn't see anyone get attacked, but a man was standing just outside the van with a paramedic kit."

A Serco spokesperson said: “A prisoner who was being transported in one of our vehicles this morning to Swindon Magistrates Court assaulted one of our officers, who has been taken to hospital to treat a head injury. The Police subsequently rearrested the prisoner.”

Wiltshire Police added in a statement: "A man in his 20s was being transported from custody to court when he tried to injure himself.

"A security van guard was assaulted when attempting to assist and required hospital treatment for a head injury.

"Two police officers were also assaulted, receiving minor injuries."