More than 60 titles in the programme, ranging from shorts and documentaries to full-length narrative features, have been given the rating.

The F is given to any film written by a woman, directed by a woman or featuring women in significant on-screen roles.

Any film that meets all three criteria is awarded a Triple F-Rating.

Titles deserving of this so-called "gold standard" include this year's opening night film Princesita, a Chilean drama about a girl raised in a cult.

Others include Gwendolyn, a documentary about an Austrian weightlifter in her sixties; the French drama When Margaux Meets Margaux; and Dykes, Camera, Action!, a history of lesbian cinema from the '80s to the present.

Gwendolyn tells of an Austrian weightlifter based in London

Initiated by FilmBath, previously Bath Film Festival, in 2014, the rating has since been adopted by the Barbican in London, the Irish Film Institute and numerous other organisations.

Raindance, which kicks off later and runs until 7 October at various venues in central London, is the first "Top 50" film festival to adopt the system.

The festival, which began in 1992, is considered one of the "50 Film Festivals worth the entry fee in 2018" by Movie Maker magazine.

Organisers said they had adopted the F-rating "because we are committed to all aspects of inclusion both in front of the screen and behind the camera".

Its adoption follows last year's decision by the Internet Movie Database (IMDb) to tag more than 21,000 films with the new classification.

 Blackbird, a film made by and starring Michael Flatley, is also part of the programme

Raindance made headlines in 2013 by giving Wikileaks founder Julian Assange a spot on its jury, a role he fulfilled by watching DVDs at the Ecuadorean embassy in London where he has resided since 2012.

This year's jury - which includes Adrian Lester, Ray Winstone and Michael Flatley of Riverdance fame - is not quite so contentious.

Flatley also has a film showing at the festival - Blackbird, a romantic thriller about an ex-secret agent who opens a nightclub in the Caribbean that he wrote, directed and stars in.

The film has yet to have a UK release date and is not F-rated.