A more or less comprehensive list of the films which at one time or another have been (and in some cases still are) banned in the UK, along with notes on the history of each one, courtesy of Melonfamers.
It isn't as comprehensive as I would have liked but the following films are either banned (how ironic) by Letterboxd or have not proved possible to track down:
Appointment with Lust (1970)
Arrowhead (1995)
The Awakening of Emily (1976)
Birds Mean Business (1968)
Black Market of Love (1967)
Blew! (1976)
Boys Just Wanna Have Fun (1999)
Brave, Bashed, Battered and Bruised (1997)
A Brief Encounter (1997)
A Caning for Miss Granger (2000)
Chained (1986)
Changing Room Exposed (1998)
The Classic Films…