Stephen Binch, 20, who was being held on remand in Lincoln jail in connection with burglary charges, appeared at Mansfield magistrates court last Thursday on unrelated charges, and was then released.
Chief Superintendent Robin Searle, head of Mansfield police, said: 'At the time of his release he was under the care and control of Group 4. To have a person remanded to custody is difficult enough these days. To have him released in this way is to say the least disappointing. '
Michael Hirst, director of Group 4 court services, said that it was not known at the time that Binch was required to appear in another court. 'It must be appreciated that persons cannot be retained in custody without clear instructions from one of the criminal justice agencies on whose directions we act.'
Even before the Mansfield incident, Derek Lewis, head of the prison service, had said that he was concerned about the escapes. He has demanded an explanation from Group 4, launched an investigation and summoned executives to a meeting this week, when he will insist they tighten their procedures.
He will also look at the role of the Prison Officers Association. Sources say that some members may have added to Group 4's troubles by being extremely un-cooperative in the release of prisoners.
The Prison Service said yesterday: 'We are extremely concerned about this escape. It will be on the agenda when the director general talks to Group 4. We cannot pre-empt what he might have to say.'
Group 4 has a five-year contract covering prison escort work in North Yorkshire, South Yorkshire, Humberside, Leicestershire, Lincolnshire, Nottinghamshire and Derbyshire.
Last Monday, the first day of the contract, a prisoner fled from Hull magistrates' court and was on the run for two days. The next day a prisoner being escorted from Lincoln Prison to Spalding magistrates' court forced open a hatch in a van and escaped. He was recaptured 15 minutes later.
On Thursday, Gary Salesman, 20, who was being escorted from court in Derby escaped through a van window.
Group 4 has responsibility for 100,000 prisoner movements a year. The Home Office is responsible for monitoring the escort service. Officials send private reports to the prison service agency.
Leading article, page 15