THE hunt continued today for a violent prisoner freed by two masked gunmen from an ambulance, following two previous escapes.

Joe Farnan, who was serving an indeterminate public protection sentence for robbery and possession of firearms at Wormwood Scrubs prison in West London, escaped from the back of an ambulance in broad daylight yesterday afternoon.

The 27-year-old had been taken to Hammersmith Hospital after apparently collapsing in jail.

As the ambulance arrived at the hospital, just a few hundred yards away, its rear door was opened and two men wearing balaclavas - one with a handgun - were waiting outside.

The masked men threatened three prison officers travelling with Farnan and forced them to uncuff him before making off in what police believe to be a silver Volvo.

Mark Leech, editor of the Prisons Handbook for England and Wales, questioned why Prison Service intelligence failed to pick up what appeared to be a pre-planned escape.

He said: "The fact that three prison officers were sent to escort him, rather than the usual two, shows there was a heightened awareness of the need for care in his case.

"However this escape was clearly pre-planned and the Prison Service needs to look urgently at why its intelligence system, which is designed to discover such plans, failed to do so."

Dee Edwards, from campaign group Mothers Against Murder and Aggression said it "beggared belief" that the convicted gunman was taken outside the prison despite having previously escaped on two occasions.

Ms Edwards said: "I am appalled at the slackness of the prison service.

"There has got to be some tightening up and some changes."