To mark its 75th anniversary, the British Film Institute asked 75 key figures 'from the world of film and current affairs' to choose the one film they would most like to share with future generations.

It's an interesting line-up - not one of those utterly predictable critics' selections that are always won by Citizen Kane, nor one of those equally guessable readers' polls that are always led by Lord Of The Rings. In fact, neither title features on the list.

One thing that surprised me is how many recent pictures were chosen. It's easy to concur with picks like Apocalypse Now (Martha Fiennes), The Third Man (Adrian Wootton and Stephen Frears) or Vertigo (Lizzie Francke), but what about Adulthood (Ashley Walters), Friday Night Lights (Max Minghella) or This Is England (Jason Solomons)'

It's true that the question the 75 respondents were required to answer was more complex than 'What's your favourite film'' or even that old late-night festival teaser: 'If you could own only one DVD, what would it be'' But selecting which film you'd most like to share with future generations is surely another way of saying the title you choose is a classic - or is heading that way.

Critical anxiety

I've long been fascinated by the question of how - or if - it's possible to recognise a classic movie at the time it comes out. There's possibly an ounce of anxiety in this. We all know the stories about critics who got it spectacularly wrong - and though I would love to adopt the Kenneth Turan defence ('I am not now, nor have I ever been, mistaken in my judgment of a film'), I do not have the LA Times critic's debonair old-school self-confidence.

But then again, it would hardly ever occur to me to predict a film is destined to become a classic. This is not so much for fear of being wrong but because classic status is an intangible and subjective quantity that is only partly to do with something inside the film. It has at least as much to do with how that film evolves over time, the chords it strikes for future generations. It even depends, to a certain extent, on the film being misread by the future.

Take the most popular choice in the BFI poll - Powell and Pressburger's A Matter Of Life And Death, which garnered four nominations. When it was released in 1946, this delightful romantic parable about an airman suspended between life and death was greeted with decidedly mixed reviews. The Daily Mail's Fred Majdalany concluded that 'the film as a whole turns out to be an elaborate joke that doesn't quite come off'. The Observer's CJ Lejeune complained that it 'leaves us in grave doubts whether it is intended to be serious or gay'. An anonymous Variety reviewer opined that 'less desire to exhibit alleged learning, and more humanity, would have resulted in a more popular offering'.

A fascinating curiosity

We read these judgements with a smile today, but the odd thing is that none of them are quite off the mark. A Matter Of Life And Death is a very strange film: this is part of its fascination. But it's also a film whose propaganda origins (it was commissioned to foster understanding between the Brits and their US wartime allies) would have been a lot more legible back in 1946. A review written for the Moscow arts journal Kultura i Zhizn by a Soviet Russian in London is not imperceptive in its analysis: 'The spectator will be persuaded by the mystical argumentation contained in the film that a joint Anglo-American policy is a panacea for all the evils threatening 'dear old England'.'

What most of these contemporary reviews missed was the sheer fairy-tale magic of the thing - which is the note we tune into today. And the propaganda thrust of the film has faded, in time, to become a quirky sparring match between Yanks and Limeys.

So A Matter Of Life And Death has taken on its mantle of beloved British classic, at least in part, because the way we read it has changed over the years. With all due respect to Max Minghella, I doubt whether Friday Night Lights will be the subject of such a tectonic shift and found to be a diamond - but you never know.