A drama about a schoolgirl whose life changes after she witnesses a violent attack has been named best film at this year's British Independent Film Awards.
Broken, the debut feature by theatre director Rufus Norris, also picked up a best supporting actor prize for Rory Kinnear.
Psychological thriller Berberian Sound Studio won the most awards.
It received four trophies - including best director for Peter Strickland and best actor for Toby Jones.
The 15th annual awards, which honour films made mainly outside major studios, took place at Old Billingsgate in London.
Sunday's ceremony was hosted by James Nesbitt, who plays the dwarf Bofur in The Hobbit film out this week.
Broken, which stars Tim Roth, Cillian Murphy and newcomer Eloise Laurence, went into the awards as the frontrunner with nine nominations.
The story focuses on three families who live in the same cul-de-sac and are linked by a violent incident that has far-reaching consequences for them all.
Describing the win as "fantastic", first-time film director Norris told BBC News: "Hopefully it makes it more likely that I'll get the chance to make another film."
Norris's recent stage productions include London Road at the National Theatre and the opera Dr Dee, with Blur frontman Damon Albarn.
"I don't like stories where you get good people and bad people - I don't think life's like that," Norris said.
"Broken shows how people behave sometimes in really awful ways and sometimes in really good ways. And often it's to do with love, protection or fear. Those things affect us all. It doesn't mean they are terrible people."
Broken was first seen at the Cannes film festival in May, but is not released in the UK until next year.
Andrea Riseborough won the best actress prize for thriller Shadow Dancer, about an IRA member turned informer in 1990s Belfast.
Olivia Colman won best supporting actress for her role as the Queen Mother in period piece Hyde Park on Hudson.
It was Colman's second Bifa award in two years, having won best actress last year for Tyrannosaur.
Peter Strickland's Berberian Sound Studio stars Toby Jones as a meek British sound engineer who is brought to Italy to work on the sound effects for a horror film.
With the actual gore kept off-screen, the audience sees Jones create horror noises by stabbing cabbages, chopping melons and twisting the stalks off radishes.
"The thing that really fascinated me was that these are innocent everyday sounds," said Strickland. "All you do is you alter the context of them and it completely disorientates you and it's quite disturbing"
The film's four wins included best achievement in production and best technical achievement.
The Imposter, the true story of a French conman who convinces a grieving Texas family that he is their missing son, won two awards: best British documentary and a directorial debut prize for Bart Layton.
Layton said: "I'd do an interview one day convinced I understood what happened, and the next day I'd sit down with someone with a different side of the story and come away with the opposite conclusion. My job was navigating these conflicting versions."
Sightseers, Ben Wheatley's pitch-black comedy about a couple on a killing spree during a caravan holiday, won the best screenplay prize for writers Alice Lowe, Steve Oram, and Amy Jump.
Oram and Lowe developed the lead characters on the comedy circuit over several years.
"It all started with us talking about childhood experiences of family holidays and we took that concept to its extreme," said Lowe.
James Floyd picked up the most promising newcomer award for his role in My Brother the Devil.
As previously announced, Jude Law received the Variety Award for helping to focus the international spotlight on the UK.
Sir Michael Gambon was awarded the Richard Harris Award for outstanding contribution by an actor to British film.
"My whole life has been spent worrying about learning lines," he joked to the BBC. "I've never relaxed - apart from Harry Potter where I just had fun!"
Winners in full:
Best British Independent Film
Peter Strickland - Berberian Sound Studio
The Douglas Hickox Award (best debut director)
Bart Layton - The Imposter
Alice Lowe, Steve Oram, Amy Jump - Sightseers
Andrea Riseborough (Colette McVeigh) - Shadow Dancer
Toby Jones (Gilderoy) - Berberian Sound Studio
Best supporting actress
Olivia Colman (Queen Elizabeth) - Hyde Park on Hudson
Best supporting actor
Rory Kinnear (Bob Oswald) - Broken
Most promising newcomer
James Floyd (Rashid) - My Brother the Devil
Best achievement in production
Berberian Sound Studio
Best technical achievement
Joakim Sundström, Stevie Haywood AMPS IPS- Sound Design - Berberian Sound Studio
Best British short
Best international independent film
The Raindance award
The Richard Harris Award (for outstanding contribution by an actor to British Film)
Sir Michael Gambon
The Variety Award
The special jury prize