- 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.
- Laugh track
- 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 2 Episode 1: Sunday at 5pm on Drama
- Series 2 Episode 2: Sunday at 5:40pm on Drama
- Series 2 Episode 3: Sunday at 6:20pm on Drama
- Series 1 Episode 5: Monday at 2:20pm on Gold
- Series 1 Episode 6: Monday at 3pm on Gold
- Series 1 Episode 5: Monday at 7:15pm on Gold
- Series 1 Episode 6: Monday at 8pm on Gold
- Series 2 Episode 4: Sunday 7th August at 5pm on Drama
- Series 2 Episode 5: Sunday 7th August at 5:40pm on Drama
- Series 2 Episode 6: Sunday 7th August at 6:20pm on Drama