Stanley Kubrick

Clockwork Orange was not banned in the UK. It played for over I year in a major London cinema. Stanley asked Warners if they would take it off the screens in the UK ( only) because of the tabloid press blaming every mugging and robbery on the film. The Mary Whitehouse and Lord Longfords anti violence campaigns and because of threats of violence to the family.
WBs had such respect for him that they granted his wish.

Yes your right, Kubrick receive unspecified threats upon his life, so he in a sense "self censored". It was not officially banned. However, the film was a critique of the established institutions like religion, government and science in Great Britain (and other countries as well), recognizing that all violence originates from these institutions ... See Moreand trickles down to the masses. This message threatened the powers that be because it makes people think, the last thing the establishment wants is for people to think.