The escape of three prisoners from a Securicor van follows a string of breakouts from the hands of private security guards.
Police forensics examine the hijacked van in south London
Companies like Securicor and Group 4 were first awarded contracts to carry prisoners between jails and courts 10 years ago.
Since then, several of their charges have escaped either from courts or from vans en route.
Some have planned their escape, down to concealing weapons, while others have seen a chance and taken it.
At the end of 2001, a prisoner on remand in a Bedford prison was in a road crash in the Group 4 vehicle he was travelling in, on the A421 in Great Barford.
Taking advantage of the confusion he escaped, but was recaptured later.
Some though, have sought to create the fog of panic themselves, often by setting fire to the security van.
A prisoner tried to escape in 2001 by running up a motorway embankment
in Hampshire after another prisoner set fire to the van they were travelling
in. He was arrested minutes later.
Also in 2001, a prisoner serving nine years for armed robbery escaped from a
security van after lighting a fire in his locked compartment as the van refuelled at a petrol station in Burgh Heath, near Banstead, Surrey.
The man broke free and escaped in the confusion as his guards opened the doors.
Coolly, he knocked on the doors of nearby houses claiming his car had caught fire and was given shelter in one.
He was recaptured by police within a few hours after a resident became suspicious and called the police.
In a particularly nasty case in 2000, a prisoner escaped after setting fire to a security van, forcing the two guards to stop and open the doors and then stabbing them in the face.
The man used a pen or small knife to stab a male guard's face and hands and slash the throat of a female guard.
She also suffered a suspected broken jaw.
In 1999, a 17-year-old remand inmate also escaped from a prison van after the
vehicle caught fire near a motorway roundabout. He was recaptured.
The youth, who was facing a charge of possessing an offensive weapon, had run
off near junction 16 of the M1 close to Kislingbury, Northants.
Most escaped prisoners have been recaptured.