Actor Aaron Johnson as a young John Lennon in a scene from Nowhere Boy in an image courtesy of Icon Film. REUTERS/Handout

The London film festival closes on Thursday with the world premiere of Nowhere Boy, about John Lennon's rebellious teenage years and his torrid relationship with his aunt and mother before the Beatles were formed.

The directorial debut of video artist Sam Taylor-Wood, the movie stars Aaron Johnson as an angry, confused Lennon who struggles to understand why his mother Julia left him with his aunt Mimi when he was a small boy.

The film plays on the contrast between his buttoned-up, straight-laced aunt, played by Kristin Scott Thomas, and his fun-loving mother (Anne-Marie Duff) who encourages him to listen to rock'n'roll and teaches him the banjo.

Asked how reliable her account of the star's troubled youth was, Taylor-Wood told BBC Radio:

There are often versions of truth. Maybe if you'd spoken to Mimi she'd have had one version and Julia, his mother, would have had another version. So as much as possible I think it's pretty close.

She also confessed that tackling a subject as revered as Lennon in her first feature film was daunting.

I think I went into it fairly naively, said the 42-year-old.

It wasn't really until I spent a lot of time in Liverpool and walking around that it started to dawn on me the magnitude of the subject matter I'd taken on. And there were moments when I thought, 'I just can't handle this, this is too big.'

DEBT TO MINGHELLA

The script was written by Matt Greenhalgh, who won acclaim for his screenplay for another rock biopic Control, about the life and death of Joy Division frontman Ian Curtis.

Greenhalgh said he went to Liverpool in northern England and visited the area where Lennon grew up as well as St. Peter's Church Hall where he famously first met Paul McCartney.

His story traces the formative months of The Beatles and ends with the band about to leave for Hamburg, an early step on their way to becoming the most successful pop act in history.

It's always nice to think of characters as kids because you can actually create them -- it doesn't come with too much baggage, Greenhalgh said in production notes for the film.

Taylor-Wood, best known for her video installations and a string of celebrity subjects and friends, switched to film with the encouragement of the late director Anthony Minghella.

He gave me the confidence because he genuinely believed I could do it and told me so, she said.

The gala screening of Nowhere Boy marks the end of the 2009 London film festival, which has lasted 16 days and showcased around 200 feature films.

The annual event is attempting to compete with major international festivals like Venice and Cannes, and this year introduced a best film award which brings it closer into line with its rivals. French drama A Prophet scooped the prize.

The majority of its movies have already been shown elsewhere, however, with only a few exceptions including Wes Anderson's animated Fantastic Mr Fox, which opened the festival and ensured George Clooney was on the red carpet.

London