In the John Landis film An American Werewolf in London, there was scene set in a cinema showing a spoof porno movie - also directed by Lohn Landis.
I’ve read that the cinema was meant to have been just off Piccadilly Circus in London, and the entrance is now a fast food/pizza joint.
Looking at Picadilly Circus, this means the cinema must have been in the north corner and on the north side of the start of Shaftesbury Avenue. I was a regular cinema goer in the centre of London at this time and I don’t remember a cinema there — and I remember several others nearby that have sadly closed.
Did it ever really exist?