Prison officers have voiced concern about a pilot scheme that gives inmates more freedom to move around jails unsupervised.

The scheme, which is being extended to Arnhem following earlier trials in Dordrecht, Heerhugowaard and Zaandam, allows prisoners to come and go from their cells freely until 9.30pm. They are given a key to the cell and a digital screen that they can use to make appointments or order groceries.

The inmates have to ensure they are on time for work and other duties, but are otherwise free to mingle with other prisoners. Wardens say it makes it harder to monitor their interactions and make sure they are not carrying out criminal activities behind their backs.

The justice ministry says the scheme is designed to encourage prisoners to be more responsible and self-reliant, but Rob Minkes, chair of the prison officers’ council COR said many staff viewed it as a ‘crude measure to cut prison personnel.’

‘There is not enough supervision for these guys,’ Minkes told the AD. ‘These prisoners are allowed to do everything unsupervised. That increases the risk that they will continue with their criminal affairs, because they can talk to each other at length and uninterrupted. It also makes it easier to do things like drug dealing.’