The real story about the black-and-white sequences is that we were filming in this chapel in Cheltenham, a very old chapel and we couldn't get the lights in there. So Lindsay said, 'Well, we'll shoot it in black and white'. When he saw it he said, 'Aah, I just love black and white, why don't we do it again tomorrow? Let's shoot it in black and white'. It was totally arbitrary. He said to me, 'Malcolm. In Cinderella when the clock strikes 12, why does the carriage turn back into a pumpkin?' I said, 'I don't know'. He said, 'It just does'. It was my first taste of surrealism.

cf clockwork orange. no specific intent to element other than directing awareness toward perception: "question your goggles. guardian says "visual/emotional transitions"-

"Like the film, Mick Travis and his two friends are apolitical [?]. They're in revolt against an autocracy that denies them individual freedom in the name of fossilised abstractions: Obedience, Team Spirit, Tradition, Duty. "When do we live?" Mick Travis asks. "That's what I want to know." They first start to live by celebrating erotic freedom (Mick's affair with a local waitress, Wallace's romance with a junior boy [missed that]), and finally erupt in furious, orgasmic liberation on Founders Day. In 1932, when Vigo's children hurled tin cans and old shoes from a rooftop, it was an innocent prank. In 1968, when the trio and their lovers open fire on school dignitaries, staff and parents, they mean business. But so does autocracy. Led by a military Founder, it fires back with superior weapons from the school armoury, and a close shot of Mick continuing to fire fades abruptly to a black screen, with If... reappearing in red letters. This final transition from fantasy to reality suggests that the revolution is doomed to failure, but a failure that's also a warning."

also,

The latter [Anderson] may have been part of British cinema's New Wave, but that didn't stop him from sometimes behaving as if he was a retired Brigadier. Surprisingly, this scourge of Albion lived for much of his life in a cottage in the heart of the Home Counties. "His favourite paper was The Daily Telegraph," says Sherwin. "He believed in hanging. I think he thought Mrs Thatcher was doing OK. I met some of his communist left-wing colleagues at a film festival in Portugal recently and I loved teasing them, saying he couldn't stand silly old fools like you."

[...]

The film-makers didn't let the school authorities know how the movie was going to end. Sherwin presented them with a dummy script and told them that the battle sequence would be filmed in Lindsay Anderson's "improvising documentary style". He pointedly declined to mention that the schoolboys would be turning their guns on the headmaster

If... (financed by Paramount after every British company had turned it down) won the Palme d'Or in Cannes despite the British Ambassador's demand that it be withdrawn from the festival. (He called it "an insult to the British nation".) It was embraced by audiences everywhere from Communist Czechoslovakia to Fascist Portugal. Back home at Cheltenham, the response was more muted. "They were very upset and a lot of boys were taken out of the school," Sherwin recalls dryly.

[...]

Sherwin and Anderson had their disagreements. The writer was extremely sceptical about the director's plans for making a sequel to If... in the early Nineties. "I'm afraid to use the phrase, but it was Lindsay's wank. It wasn't real. He was my greatest friend and so naturally I decided to do what I could."

re: free cinema..

Founded on the ideology and practice of Neorealism, the Free Cinema movement emerged with a larger social movement, assailing the British class structure and calling for the replacement of bourgeois elitism with liberal working-class values. In the cinema world, this anti-establishment agitation resulted in the New Cinema, or social realist movement, which was signaled by Reisz's Saturday Night and Sunday Morning (1960), the first British postwar film to have a working-class protagonist and proletarian themes.

Stylistically influenced by the New Wave, with which it was concurrent, the 'social realist' film was generally shot in black and white, on location in the industrial Midlands and cast with relatively unknown young actors and actresses. Like the New Wave films, social realist films were independently produced on low budgets (many of them for Woodfall Film Productions, the company Richardson and playwright John Osborne founded in 1958, principally to adapt the latter's Look Back in Anger), but their freshness of both content and form attracted an international audience. Some of the most famous were Richardson's A Taste of Honey (1961) and The Loneliness of the Long Distance Runner (1962), John Schlesinger's A Kind of Loving (1962) and Billy Liar (1963), Anderson's This Sporting Life (1963), and Reisz's Morgan: A Suitable Case for Treatment (1966).