Minghella's love letter to London

"Oh no," he says, "it's not a film about an ideological dispute, it's a film about how, in a world that's decent to you, it's much easier to be decent to each other. Probably the least guilty person in this story is the person who commits the crime."

Minghella first got the idea for the film a decade ago, when he tried - and failed - to write a play about a breakin where nothing was taken but things were added, provoking a crisis in the homeowner's marriage. The idea, he says, is "that a break-in could actually rupture a marriage and then in some ways fix it. That was how the idea formed: to examine how a burglary could damage a lot of things and then heal them at the same time."

His new film is not the only thing on Minghella's agenda, at the moment. When he is not writing or directing films (or plays, operas or dance events), he heads the British Film Institute, sits on the Culture and Creativity Advisory Forum for the 2012 Olympics, actively supports the Labour Party and is a pal of Gordon Brown.

As BFI chair he is championing the new National Film Theatre - rebranded BFI South Bank - which opens next February, three-and-a-bit years on from when, newly installed as chairman, he made a passionate opening speech at the 2003 London Film Festival about his aspirations for what was then a somewhat troubled body.

BFI South Bank will be state-of-the-art, with a "Mediatheque", galleries, project spaces and lots of other bells and whistles. "It's going to be a great illustration of what the BFI is," he says.

"It will give visitors the opportunity to encounter films and have them contextualised. It will join up all the dots of the BFI in one building - the aspiration of trying to get as many people as possible to collide with world cinema. I've waited since that speech to say that here was a place you could have the whole BFI experience."

Minghella is also in the early stages of planning a series of events for the Olympics, but what he really wants for 2012 is a new monument to British film, a purpose-built flagship building.

"What we are trying to do is to give ourselves another six or seven years on the South Bank and use that space as well as we can, in the years it has left. It was constructed in the middle of the last century, it's under an arch and it's fraying at every edge.

"Film is the most popular medium, yet we don't have anything comparable to the Royal National Theatre, the Festival Hall for music...or the opera house. We certainly don't have anything that can shake hands with the new technologies of the 21st century, that can become a real palace of film knowledge."

Minghella is not sure about the best location for this cathedral to cinema. "We need to find a site that can accommodate us in the timescale. We would love it to be open in time for the Games, to be one of the buildings that says London is a world city, with the kind of film facilities that that implies. It's not that BFI is looking to leave the South Bank, but we might have to, if we can't find a way of creating the kind of building we think London deserves.

"It's obviously got to be a focal point, a flagship for Times-BFI London Film Festival. It also needs to have access to our collections, our archives, a place for premieres to take place, and it needs a first-class screen. If you can watch the movie on a good home stereo sound system with a great screen, what is bringing you out to the cinema unless the cinema is extraordinary, unless the sound is extraordinary, unless the experience is extraordinary?"

Is there not a danger, though, that we might end up with a spanking new film centre in 2012 and no British films to show in it? At pains to point out that he doesn't speak for the industry, Minghella insists that times are good and the mood is buoyant. "We are a country that seems to love movies but that also loves to worry about the health of British film. I think we are in rude health."

But it's the difficulty of financing films that we hear so much about. Minghella's movies are made by Miramax, "but the money doesn't come from them. If you try to trace the provenance of money in film it's an interesting game: it doesn't stop at America, it weaves its way back into Europe.

"I don't think we should be concerned too much where it comes from, we should worry about where it's being spent, and if it's being spent in Britain that's a good thing. We're a leading centre for post-production. We have great studios, great technicians, and currently a very successful group of writers and directors. There's no reason to assume that won't be the case in half a dozen years' time."

Minghella now lives in Hampstead with his wife, Hong Kong-born choreographer Carolyn Choa, whom he met in Hull and who has worked on most of his films. Their son, Max, is an actor (he was the male lead in Bee Season and played George Clooney's son in Syriana). Indeed, their lifestyle is not a million miles away from that of Will in the film. Their house was even broken into recently. Under the circumstances, how did that make him feel?

"Not good at all," he concedes. "It's not that I'm endorsing breaking and entering. I'm just saying that sometimes we need to understand why these things happen." Minghella, it seems, is a man very much in control.

Breaking and Entering screens at the London Film Festival on 27 October and is released on 10 November.