- Part of
- Production company
- Pilot episode filmed on location in Wales.
The front gate is of the Main Gate House, of former St Albans Prison, Victoria Street, St Albans, Hertfordshire.
The communal areas of the prison were filmed in a water tank at Ealing Studios.
External scenes were filmed at various London psychiatric hospitals.
Most of the other interior scenes, such as Fletcher's cell, were filmed at BBC Television Centre.
- Theme tune composed by Max Harris. Introductory sentencing performed by Ronnie Barker.
- First broadcast
- Sunday 1st April 1973 on BBC Two at 8:15pm
- Last new broadcast
- Friday 25th March 1977 on BBC One at 8:30pm
- Upcoming repeats
- Series 3 Episode 1: Tomorrow at 5:45pm on Gold
- Series 3 Episode 2: Tomorrow at 6:20pm on Gold
- Series 3 Episode 1: Tuesday at 12:05pm on Gold
- Series 3 Episode 2: Tuesday at 12:45pm on Gold
- Series 3 Episode 3: Tuesday at 6:55pm on Gold
- Series 3 Episode 4: Tuesday at 7:40pm on Gold
- Series 3 Episode 3: Wednesday at 12:05pm on Gold
- Series 3 Episode 4: Wednesday at 12:45pm on Gold