Blues-steeped vampire epic Sinners and gothic horror story Frankenstein won three awards each, while Shakespearean family tragedy Hamnet won two, including best British film.
One Battle After Another, Paul Thomas Anderson's explosive film about a group of revolutionaries in chaotic conflict with the state, won awards for directing, adapted screenplay, cinematography and editing, as well as for Sean Penn's supporting performance as an obsessed military officer.
"This is very overwhelming and wonderful," Anderson said on Sunday as he accepted the directing prize.
"We have a line from Nina Simone that we used in our film, 'I know what freedom is: It's no fear,'" he said.
"Let's keep making things without fear. It's a good idea."
Bookies' favourite Jessie Buckley edged out Australia's Rose Byrne to win best actress for playing grieving mother Agnes Hathaway, wife of William Shakespeare, in Hamnet.
In a major upset, Robert Aramayo won the rising star award and best actor for his performance in I Swear, a British indie drama about a campaigner for people with Tourette's syndrome.
The 33-year-old British actor looked stunned and called the victory over Ethan Hawke, Michael B. Jordan, Leonardo DiCaprio and Timothée Chalamet "absolutely mad".
"I absolutely can't believe this," he said.
"Everyone in this category blows me away."
Sinners took home trophies for director Ryan Coogler's original screenplay, the film's musical score and for Wunmi Mosaku's supporting actress performance as herbalist and healer Annie.
Hollywood stars and British celebrities, from Paddington Bear to the Prince and Princess of Wales, gathered at London's Royal Festival Hall for the awards.
DiCaprio, Chalamet, Emma Stone, Cillian Murphy, Glenn Close and Ethan Hawke were among the stars walking the red carpet before a black-tie ceremony.
Prince William and Catherine, Princess of Wales also attended, three days after William's uncle Andrew Mountbatten-Windsor was arrested by police and held for 11 hours over allegations he sent sensitive government information to the late financier and sex offender Jeffrey Epstein.
The scandal has rocked the royal family led by King Charles III, though William and Kate remain popular standard-bearers for the monarchy. William is due to present an award in his role as president of the British Academy of Film and Television Arts.
The BAFTA Film Awards, often provide hints about who will win at Hollywood's Academy Awards, held this year on March 15.
Sinners has a record 16 Oscar nominations, followed by One Battle After Another with 13.
One Battle went into the BAFTAs ceremony with 14 nominations. Sinners was just behind with 13, while Hamnet had 11.
Ping-pong odyssey Marty Supreme also had 11 nominations but went home empty-handed.
Guillermo del Toro's reimagining of Frankenstein and Norwegian family drama Sentimental Value each got eight nominations.
Frankenstein took awards for production design, costume design and for the hair and makeup artists who spent 10 hours a day transforming Australia's Jacob Elordi into the movie's monstrous creature.
The best-documentary prize went to Mr Nobody Against Putin, about a Russian teacher who documented the propaganda imposed on Russian schools after the invasion of Ukraine.
The film's American director David Borenstein said that teacher Pavel Talankin had shown that "whether it's in Russia or the streets of Minneapolis, we always face a moral choice," referring to the protests against US immigration enforcement in Minnesota.
"We need more Mr Nobodies," he said.
