A few weeks back, a film called Margaret slipped silently into cinemas. Directed by Kenneth Lonergan, it turned up completely unannounced by Fox Searchlight in London's Odeon Panton Street. It made £4,595 in its opening weekend. From one screen. Not bad for a film that was made in 2005.

Shot around the same time as the phenomenal The Squid and the Whale, Anna Paquin took on an equally intriguing role as Lonergan's lead.

Lisa, a young student who inadvertently causes a bus crash, finds herself cradling a woman as she dies in the street, bleeding all over her hands. Afterwards, she tries to deal with her guilt by putting the blame on bus drive Maretti (a typically decent Mark Ruffalo). And so she joins forces with the deceased woman's best friend, Emily (Jeannie Berlin), to sue him. 

As the legal proceedings continue in exhausting detail, Lisa starts getting into loud arguments at school over politics and terrorism. And gets off with the class drug dealer (Kieran Culkin). And makes moves on her teacher (Matt Damon). Meanwhile, Lisa's mum (J. Smith-Cameron) fights on with her acting career, eventually dating a mildly racist man who likes going to the opera (Jean Reno). 

Is this Lonergan's take on post-9/11 America? Lisa struggling to accept her perceived role in a tragic loss of life while aggressively drawing in all those around her? Or is it a lyrical ode to fallen youth, a la Gerard Manley Hopkins' Spring and Fall, the poem which gives the film its title? Both seem to be the intention of this sprawling coming-of-age tale - Lisa's worn-out teacher (a scene-stealing Matthew Broderick) even gives Hopkins' verse a decent reading - but the 150-minute runtime soon descends into a montage of pretty skyscrapers, in-depth discussions of punitive damages and shots of people doing their best "We're watching the opera" faces. 

"We're not supporting characters in your life story," Emily reprimands Lisa at one point. The problem is that they are - and Margaret can't choose who to focus on, leaving Matt Damon feeling irrelevant, Matthew Broderick feeling wasted and Jean Reno feeling mildly racist.

Lonergan's lengthy drama has sat unreleased for six years because the director couldn't work out how to finish it. Eventually Martin Scorsese and Thelma Schoonmaker came along and chopped 30 minutes out to produce a final edit he was satisfied with. It's a shame they didn't keep cutting. There's an interesting and challenging film in there somewhere (perhaps even that mooted Oscar-worthy performance from Paquin) but it's surrounded by too much stuff. 

On the bright side, Margaret is now showing in 23 UK cinemas. Go see it - it's an interesting watch.