The BBFC is a non-government organisation nevertheless required by the government to view and rate all films. Councils licence cinemas (originally for fire safety) and require cinemas to only show rated material to the public, but they also have a discretionary power to rate and therefore ban films themselves.
As an example, Life of Brian (1979) was only an “AA” (14 years+) but a moral panic made 28 councils raise to an “X” (18+) and 11 actually banned it completely.
(For clarity, a film is de facto banned when either the BBFC or a local council refuses to rate it. It can still be shown privately (eg at a film society) provided it doesn’t contain illegal material (ie it’s not obscene))
As an example, Life of Brian (1979) was only an “AA” (14 years+) but a moral panic made 28 councils raise to an “X” (18+) and 11 actually banned it completely.
(For clarity, a film is de facto banned when either the BBFC or a local council refuses to rate it. It can still be shown privately (eg at a film society) provided it doesn’t contain illegal material (ie it’s not obscene))