What drove you to make a film about cinema and childhood?
Children aren't afraid of their desires for things. If you make a film about children, you make a film about naked adults - what lies beneath.
You've cited Picasso's quote about all children being artists.
It's so true. At a QA for the film, my niece and nephew - they're in the film - drew me with a monkey head. But around about the time of self-consciousness, children's drawing gets conventional. We have to undo that.
In The First Movie, you introduced cinema to Iraqi children who had never experienced it. What was the most memorable response?
One 10-year-old boy took a camera, started filming another boy playing with mud beside a river, and said: "He's putting his dreams into the mud." I could never have scripted that.
You've said Hollywood often presents "an adult fantasy of childhood". What did you mean?
American culture has this idea that we can all be the heroes in our own lives. Children in American cinema are great sometimes, but they're little heroes, like Elliott in E.T. In Japanese cinema, children are more shy, cautious and scared about the world. Iranian cinema has the fullest depiction of childhood: children are really annoying and aggressive. Iranians describe what children are actually like.
What's your favourite film about childhood?
Willow and Wind, from Iran. It's about a little boy who breaks a school window and decides to replace the glass himself, on a really windy day. He puts his exercise book between it and his chin so he doesn't slit himself; you see the glass bend in the wind. It's a great film about how dogged kids are. There's another from Latvia, Ten Minutes Older. It's a shot of a boy's face for 10 minutes. In that time, he gets older, the world gets older and we see a whole range of emotions.
What was your favourite film in childhood?
I watched Grease a lot. It's about a mysterious summer that's already over, but they're still singing and talking about it. As a boy, I thought it must have been amazing.
Is cinema still underappreciated in education, compared with, say, literature?
I think so. One big problem is that teachers often haven't had the benefit of a film education, so they can't confidently show examples from film to demonstrate a point. If teachers in every area of education are not referring to film, we're doing something wrong.
Is it a particularly British problem that cinema is still considered frivolous?
Yes, in Scotland in particular. Scotland is so good at the word, but if you believe that the word is a separate thing, then you are going to be sceptical about imagery.
Why is it important to have a strong national cinema?
A huge thing happens in the confidence of a person and a nation when it sees itself in that luminous, charmed realm - the big screen. We often think the movies are a fantasy world over the rainbow, but when you see Gregory's Girl on the big screen, or Trainspotting, especially when these films do well, it puts a piece of the jigsaw into your identity.
What would you say to young people who want to make films?
They shouldn't copy what they've already seen - please don't try to make a Tarantino film or a romcom. Too often we think we have to copy Hollywood traditions, but so many Hollywood films are shit. The most creative thing you can ask yourself is: "What haven't I seen on screen before?" and make a film about that. It's likely to be something you know.
You were educated in what you describe as an "oppressive" school run by nuns. Did your schooldays propel you forward or hold you back?
You can gain an appetite by being given lovely, succulent things - or having them withheld from you. I was given a lot in my art classes, but in English things were off limits, like James Joyce. Overall, I think it was great. Even though I profoundly disagreed with the conservative curriculum, I was curious about what they didn't let us see.
What's your impression of teaching today?
When I went to school we had to be our own hard drive; now everybody has multiple hard drives. If the issue isn't retention of information now, it's something like intoxication.
You've talked about being bullied at school - what advice would you give to someone experiencing that?
It'll get better. It teaches you things at too young an age, but children have to learn at some stage that life's tough. If they're forced to know what sadness is quite early, that'll benefit them in the long run.
What was the highlight of six years making The Story of Film?
Going to Ouagadougou in Burkina Faso, West Africa. The city's central monument isn't to some king or queen, or somebody who benefited from the slave industry; it is to cinema. In the 1980s, literacy levels for young people were 6 per cent. If you can't read or write, you still need to know what life's about, you still need to find your place in the world. How did people do it there? Through the movies. That touched me very much.
Born: Belfast, 1965
Education: St Louis Grammar School, Ballymena; University of Stirling, film and media studies and fine art
Career: Film-maker and author. Wrote and directed The Story of Film: An Odyssey (2011), a 15-hour documentary series. Established the 8 12 Foundation with Oscar-winning actor Tilda Swinton, introducing Scottish children to classic, world and avant-garde cinema. His A Story of Children and Film was the only British film in the official selection at this year's Cannes Film Festival.