Sean Ellis picked up the prize for Best Director for helming the movie, which also won for Best Achievement in Production.
Lindsay Duncan earned the title of Best Actress for "Le Week-end" and James McAvoy won the Best Actor accolade for "Filth."
Imogen Poots collected her BIFA for Best Supporting Actress for "The Look of Love" and Ben Mendelsohn took home the Best Supporting Actor trophy for "Starred Up."
"This year our independent jury had an extremely tough job. They were asked to choose from an impressive pool of talent and creativity in a year where the diversity of storytelling is more extreme than ever," ceremony directors Johanna von Fischer and Tessa Collinson said in a joint statement. "Thanks to an independent film industry which encompasses so many different cultures, personalities, visions and voices, Britain is producing a new generation of fearless artists both behind and in front of the camera who represent that richness of our diverse British society. With so many of the films exploring themes about being less judgmental and more forgiving, this perhaps reflects a movement within British independent film-making that brings much hope for the future."
Northern Irish actor James Nesbitt served as host of the event at Old Billingsgate.