The three-and-a-half-hour-long epic also took best director, best original score and best cinematography.
Conclave has taken the top prize at this year's BAFTA film awards, winning best film as well as outstanding British film.
Body horror The Substance took a well-deserved win for best makeup and hair, despite Moore missing out on the best actress win.
Kieran Culkin, 42, won best supporting actor for his role in comedy A Real Pain, with his co-star and the film's writer Jesse Eisenberg accepting the gong on his behalf due to a member of Culkin's family being unwell, meaning he was in New York to be by their side.
Emilia Perez, which has come under fire in recent weeks following resurfaced tweets from its lead star Karla Sofia Gascon, took best film not in the English language.
