The ferocious female-led tragi-comedy Three Billboards Outside Ebbing, Missouri was the big winner at the British Academy Film Awards in London, where women demanding an end to harassment, abuse and inequality dominated the ceremony. Martin McDonagh’s film about a bereaved mother seeking justice won five trophies on Sunday, including best film, outstanding British film and best actress, for Frances McDormand.

Allison Janney was named best supporting actress for playing ice skater Tonya Harding’s domineering mother in I, Tonya. Guillermo del Toro won the directing prize for the monster fantasy The Shape of Water, which also took trophies for music and production design. Gary Oldman, the favourite among bookies, won the best actor prize for playing wartime British Prime Minister Winston Churchill in Darkest Hour.

The British prizes, known as BAFTAs, are considered a key indicator of likely success at Hollywood’s Oscars in two weeks' time. The film awards season in the United States and elsewhere has been overshadowed by the allegations of sexual harassment and abuse leveled at scores of entertainment figures since women began coming forward to accuse Hollywood producer Harvey Weinstein last year.

The red carpet and the auditorium at London’s Royal Albert Hall were a sea of black, as actresses such as Lupita Nyong’o, Angelina Jolie, Jennifer Lawrence and Margot Robbie eschewed colour as a statement against sexual misconduct and gender inequality. Several actresses brought feminist activists as guests, and men showed solidarity with “Time’s Up” lapel pins.

Prince William and the Duchess of Cambridge were guests of honour at Sunday’s ceremony. Kate acknowledged the evening’s muted fashion by wearing a dark green Jenny Packham dress with black belt. The call to wear black put Kate in a delicate position, because the royal family is careful to avoid political statements. Ahead of the ceremony, almost 200 British women in entertainment called Sunday for an international movement to end sexual misconduct. Kate Winslet, Emma Thompson, Naomie Harris, Emma Watson and Gemma Arterton were among signatories to a letter saying that 2018 should be “the year that time was up on sexual harassment and abuse.”