A prisoner with a history of violence is today on the run after he slipped past prison guards and security staff at the John Radcliffe Hospital, in Oxford.

Kenneth Wilson

Kenneth Wilson, 38, who is serving an 18-year sentence for robbery, was at the Headington hospital for "routine" treatment when he escaped at about 3pm yesterday.

Detectives were investigating a possible sighting of Wilson in Cowley at 7.30am today. They were also looking into a tip-off that he might be heading north.

Police described Wilson as "desperate" and warned the public not to approach him as he can be violent.

The fugitive, who has a scar on his lip and right cheek, was not handcuffed and slipped past a prison guard after the man was distracted.

Wilson was not thought to have any money on him when he made his bid for freedom.

Police officers searched the hospital grounds, with support from the Thames Valley Police helicopter, but found no trace of the convict, who was serving his sentence at Grendon Prison, in Buckinghamshire. He had been eligible for parole in two years' time.

Police stepped up patrols in the city yesterday evening and overnight to try to find Wilson.

Officers were sent to Oxford railway station and Gloucester Green bus station in case Wilson tried to leave the city on public transport. The extra patrols were continuing today.

Oxford police have contacted other police forces over possible contacts of Wilson identified by the prison authorities.

Insp Stuart Craik said: "The prisoner went to the hospital together with two prison officers for routine treatment.

"One of the prison guards was distracted and he ran out of the door.

"He wasn't handcuffed. We've had no sightings since he escaped.

"We've no idea at all if anyone has helped him escape or if it was just an opportunity he's taken.

"We've nothing to say at this stage that anyone else was involved. He's just desperate.

"He has been sentenced for violent offences, but because he's been in a prison for so long, we don't know what his behaviour will be like.

"He has no money with him and has a history of violent behaviour, so we would urge anyone who sees him to keep away."

An Oxford Radcliffe Hospitals NHS Trust spokesman said: "We have security teams here on duty 24 hours who will be on full alert until this situation is over.

"We work with the prison service when they bring in prisoners, and our teams have helped the police to search the site."

Wilson, who is Scottish but lived in Surrey before he was jailed, is about 5ft 8in. He was wearing a navy blue, long-sleeved T-shirt, jeans and white trainers.

He has a fair complexion and is bald, with a scar on his lip and right cheek.

He was 12 years into his prison sentence for a robbery.

Anyone with information about Wilson's whereabouts should call police on 01865 266000.