Baftas 2017: Dev Patel and Emma Stone win awards
La La Land has dominated the Baftas, taking five trophies - including best film and best actress for Emma Stone.
There were also awards for Lion, including best supporting actor for Dev Patel, and Ken Loach's I, Daniel Blake, which was named outstanding British film at the London ceremony.
Patel said the win was "overwhelming".
Casey Affleck was named best actor for Manchester by the Sea and Viola Davis won the best supporting actress prize for Fences.
She is also nominated for an Oscar for her role in Fences, based on the August Wilson stage play of the same name.
Manchester by the Sea also won the best original screenplay, for the text by its director Kenneth Lonergan.
You may well be tired of hearing about La La Land, but its winning streak shows no signs of slowing down.
The recognition by Bafta is a good sign for the musical - also starring Ryan Gosling - coming just weeks before the Oscars. It had been nominated for 11 Baftas in all and is in contention for 14 Academy Awards.
La La Land has already smashed the record for the most Golden Globes, winning seven prizes last month.
Stone was among the winners to make an oblique reference to world affairs, although the new US President Donald Trump was not explicitly mentioned during the acceptance speeches.
After thanking La La Land's director Damien Chazelle, who took home the best director statuette, Stone told the audience: "This country - and the US, and the world - seems to be going through a bit of a time, just a bit.
"In a time that's so divisive, I think it's so special we were able to come together tonight thanks to Bafta, to celebrate the positive gift of creativity and how it can transcend borders and how it can help people to feel a little less alone."
She beat Meryl Streep, Amy Adams, Emily Blunt and Natalie Portman, and is also in the running for an Academy Award.
Affleck, who plays a grieving handyman in gritty drama Manchester by the Sea, seemed taken aback by his win, saying: "The room looks very different from here. My heart is beating."
After the awards, he said he had spoken to Meryl Streep backstage about her recent Donald Trump speech.
Affleck said: "I told her how much her speech at the Golden Globes meant to all of us and how grateful I was that she did it and kicked in the door a little bit, and said it's OK to talk about these things and said it doesn't matter if we are actors, we have been given a microphone and we can speak out.
"She said, 'I think there is hope around the corner'."
Arrival and Nocturnal Animals were nominated for nine Baftas each, but just won one award between them.
That went to sci-fi epic Arrival, starring Amy Adams, for best sound - leaving Tom Ford's latest movie, in which the actress also makes an appearance, empty handed.
The Duke and Duchess of Cambridge were guests of honour at the star-studded ceremony, held at London's Royal Albert Hall.
The duke was there as president of Bafta to award the fellowship to veteran actor and comedian Mel Brooks.
Patel, 26, was greeted with a round of applause as he accepted the prize for best supporting actor for family drama Lion, about a man who was adopted as a child and is trying to find his family in India. He is nominated in the same category at the Oscars.
The former Skins star initially appeared speechless, saying: "Wow, that just happened", before describing the win as "so overwhelming".
He stars with Nicole Kidman in Lion, which he said is "about a love that transcends borders, race, colour, anything".
Backstage, the Briton said his family was with him for the ceremony, adding: "I used to watch this with them, in Rayners Lane on the end of the Piccadilly Line. It's an out-of-body experience."
He promised to share the award with Sunny Pawar, the young boy who plays Patel's character Saroo Brierley as a child. Lion also won the best adapted screenplay.
Ken Loach, director of I, Daniel Blake - about the struggles of living in the UK benefits system - condemned the government as he accepted the award for outstanding British film - the first of the night to be handed out.
He apologised for making a political speech so early on, but said: "Thank you to the academy for endorsing the truths of what the film says, which hundreds and thousands of people in this country know.
"The most vulnerable and poorest are treated by the government with a callous brutality that is disgraceful, a brutality that extends to keeping out refugee children we promised to help and that's a disgrace too."
'Stories deserve to be told'
Viola Davis paid tribute to her late father, who worked as a janitor and horse groomer, in her speech.
"When he took his last breath, one of the most devastating things that went through my mind is: Did his life matter?" she said.
"August [Wilson] answers that question so brilliantly, because what he did is he said that our lives mattered as African-Americans.
"The horse groomer, the sanitation worker, the people who grew up under the heavy boot of Jim Crow, the people who did not make it into history books - but they have a story, and those stories deserve to be told, because they lived."
EE's Rising Star award - the only to be voted for by the public - was won by Spider-Man: Homecoming star Tom Holland.