Escaped prisoner Andrew Farndon had fled before
A dangerous criminal who escaped as he was taken by taxi to a Suffolk hospital for treatment on a knife wound had previously fled from court.
Andrew Farndon, 26, escaped when two guards were threatened at gunpoint as he arrived at the Bury St Edmunds hospital at 18:50 GMT on Wednesday.
Detectives believe Farndon was injured as part of a pre-planned plot.
Farndon had previously escaped by leaping from the dock in 2007 while on trial over a hammer attack.
He is serving an indeterminate sentence for causing grievous bodily harm.
Police have released closed circuit television images of a gunman approaching the hospital and the two men fleeing.
Forces nationwide have joined the hunt for Farndon, whose family live in the Coventry area.
Det Ch Insp Nick Bennett, of Suffolk police, said officers were investigating whether mobile phones were used in the planning and execution of the escape.
"It smacks of something which has been planned well in advance and with associates on the outside," he said.
Officials are investigating whether Farndon inflicted a serious knife wound on himself, before being taken to the hospital's Accident & Emergency (A&E) department in a taxi accompanied by two guards.
A Prison Service spokeswoman said "vetted taxi companies" were used "routinely" to transport prisoners on visits including non-emergency medical appointments.
She said taxis were not used for "high risk" prisoners.
Farndon was rated a Category C prisoner, a security classification which meant he was considered unlikely to make a determined escape attempt.
Mr Bennett, of Suffolk Police, said a weapon had been "pressed against the prison officer's head" during the escape.
"He was handcuffed to a female prison officer who removed the handcuffs when threatened with the handgun," said Mr Bennett.
"A male prison officer was also escorting him."
It is not thought the escape is linked to that of an "extremely dangerous" category A inmate, murder suspect John Anslow, who was sprung from a prison van after it left Hewell Prison in Worcestershire on Monday.
Former convict Mark Leech, editor of the national prisoners' newspaper Converse, has called for a full inquiry into how both escapes were possible.
"Forget reform, rehabilitation or reducing reoffending, the first and primary function of the Prison Service is security - and nowhere is that brought into sharper focus than with the security of highly dangerous prisoners of whom they have lost two in a week," he said.
"How is it that security intelligence at these prisons missed completely both of these clearly pre-planned escapes?"
Justice Minister Crispin Blunt said the circumstances behind the latest incident would be examined.
A Prison Service spokeswoman said an inquiry would follow.