Prison officers yesterday criticised the authorities for using a conventional coach rather than a specialist security van.
The fugitives attacked their five-man guard and beat them with their handcuffs and truncheons while on the M25. The inmates then forced the coach driver to take them to north London, where they fled on foot on Tuesday night.
As the Prison Service began an investigation into the incident, it was revealed that the six escapees, five of whom are convicted robbers and one of whom was jailed for possession of firearms, were part of a gang at Blundeston prison, near Lowestoft in Suffolk. They were being taken to two jails in London following a string of incidents culminating in an attack on a fellow inmate.
The Prison Officers Association criticised the Prison Service for using a coach to transfer such dangerous offenders.
John Sutcliffe, assistant secretary of the POA, said: "We have been concerned for some time about the use of unsecured vehicles to transfer prisoners.
"There have been a number of escapes from coaches - we don't seem to be making much progress. It's ironic that the private sector have to use cellular vehicles (vans with separate cells)."
He added: "It is very strange that they were trying to split up the gang by taking them from a secure environment on to a standard coach."
The prisoners took control of the coach on the M25 somewhere in the region of junctions 26 or 27, in the Waltham Abbey area, on Tuesday afternoon, and ordered the driver to drive 10 miles to Duncombe Road, in Archway, north London.
It appears that at some stage some of the prisoners slipped out of their handcuffs - the inmates were cuffed together as well as having their hands secured.
Four of the five officers who were guarding the prisoners were injured in the incident, although all have been released from hospital.
Scotland Yard has warned that all six should be regarded as dangerous and should not be approached by the public.
The Prison Service confirmed that of the escapees, four were from the capital - Christopher Ward from south-east London, Lee Mitty and Stewart Warwick from north London, and Gary Staggs from east London.
David Currey and Warren Edwards were listed as being of no fixed abode. Five of the escapees were convicted robbers. Currey was serving nine years, Edwards, eight years, Ward, 12 years, Mitty 11 years and Staggs 10 years.
Warwick was serving nine years for possession of firearms.
A Prison Service spokeswoman said yesterday that all aspects of the escape would be examined, but stressed that coaches were used to transfer inmates on "thousands" of occasions without incident.
Scotland Yard continued an intensive search for the escaped men yesterday with the help of a police helicopter and dogs.
The men made off with prison officer's truncheons, money, a mobile phone and their jackets. They were wearing prison denims when they fled into a housing estate from the coach.Reuse content