Gay BDSM biker romance Pillion took the top prize at the British independent film awards (Bifas), which were announced on Sunday at a ceremony in London. Pillion also tied with real-time Iraq war drama Warfare for most awards on four, with all the latter’s wins having been previously announced.

Pillion, adapted from Adam Mars-Jones’s novel Box Hill, also picked up best debut screenwriter for its director Harry Lighton, as well as best costume and hair and makeup design. The film premiered at the Cannes film festival in May to admiring notices, including a four-star review from the Guardian’s Peter Bradshaw who called it “funny and touching and alarming – like a cross between Alan Bennett and Tom of Finland”.

Warfare, written and directed by Alex Garland and former US Navy Seal Ray Mendoza, won awards for editing, effects and sound, as well as for best ensemble performance for its seven-strong principal cast. A recreation of a real-life mission during the Iraq war in 2006, Bradshaw called it “a visceral, immersive, often skull-splittingly loud film” but also “weirdly obtuse and self-congratulatory”.

Nigeria-set drama My Father’s Shadow had led the nominations list (with 12) but in the event it picked up a single win: best director for Akinola Davies Jr. Tourette activist biopic I Swear, which had also featured strongly in the original nominations, did a little better, winning best lead performance for Robert Aramayo and best casting.

Full list of awards

Best British independent film Pillion
Best director Akinola Davies Jr, My Father’s Shadow
Best lead performance Robert Aramayo, I Swear
Best screenplay Tom Basden, Tim Key, The Ballad of Wallis Island
Best supporting performance Jay Lycurgo, Steve
Best joint lead performance Tim Key, Tom Basden, The Ballad of Wallis Island
Best ensemble performance Warfare, D’Pharaoh Woon-A-Tai, Will Poulter, Cosmo Jarvis, Kit Connor, Finn Bennett, Joseph Quinn, Charles Melton
Douglas Hickox award for best debut director Cal McMau, Wasteman
Breakthrough producer Dhiraj Mahey, Ish
Breakthrough performance Posy Sterling, Lollipop
Best debut screenwriter Harry Lighton, Pillion
Best debut director – feature documentary Myrid Carten, A Want in Her
Raindance Maverick award A Want in Her, Myrid Carten
Best feature documentary A Want in Her
Best British short film Magid/Zafar
Best international independent film Sentimental Value
Best casting I Swear
Best cinematography Die My Love
Best costume design Pillion
Best editing Warfare
Best effects Warfare
Best music supervision Die My Love
Best makeup and hair design Pillion
Best original music The Ballad of Wallis Island
Best production design Harvest
Best sound Warfare
Richard Harris award for outstanding contribution by an actor to British film Emily Watson
Special jury prize Warp Films
Cinema of the year Magic Lantern, Tywyn