The justice ministry is developing a knee lock for psychiatric prisoners which they would wear during their first periods of leave. The mechanism will automatically force prisoners into a squatting position if they stray too far from their supervisor.

Together with an electronic tagging system and an ankle band, the knee lock is part of measures announced by the justice minister on Tuesday to tackle the problem of prisoners escaping while on leave.
In a letter to MPs, Ernst Hirsch Ballin said that in the future psychiatric prisoners on home leave will be accompanied by a guard as well as a social worker. The guard, who will carry pepper spray, will be obliged to take action if the prisoner tries to escape.
There have been a number of high profile cases over the past years of crimes being committed by escaped psychiatric prisoners.