The Packhorse Cafe doesn't exist anymore. It was on the Tewkesbury Road about four miles outside Cheltenham. The road in the film is lined with Elm trees and most of them vanished in the mid-70s because of an outbreak of Dutch elm disease, they've been replaced by another type of tree.
The painting in the dining hall is Richard Platt from Aldenham School. The Hall scene was an amalgamation of the school halls at Cheltenham and Aldenham.
The scene of the beating in the gym was completely adlibbed.
The shot where Mick and the Girl are seen rolling on the café floor naked when making love was Malcolm McDowell's idea (because he wanted to see his attractive co-star, Christine Noonan, for whom he admitted having a crush, in the nude.) However, when Lindsay Anderson accepted his star's suggestion, the director required McDowell to ask Noonan if she was willing to do so. (Her reply, according to McDowell, was "I don't mind.")
The title of the film was suggested by the secretary of Memorial Films when she overheard Lindsay Anderson and David Sherwin endlessly debating possible titles.
Widely regarded as one of the films that captured the great counterculture movement of the late 60s, shooting actually began several months before one of the most significant events of that movement - the student riots in Paris in May 1968.