Leonardo DiCaprio was won the coveted best actor award for The Revenant in a closely-watched race which pitted him against Eddie Redmayne.
Picking up his award, the actor said he was "absolutely honoured" to win.
"As an actor I've been influenced by so many British actors," he said.
He also paid tribute to the director Alejandro G Inarritu, who picked up the award for best director, saying "thank you for becoming a great friend."
The best actor had been the most tightly-fought battle of the night - and DiCaprio's win will lead to speculation that he could finally pick up an Oscar this year.
Redmayne had earlier tipped his rival to win the Bafta, saying he was "extraordinary in The Revenant and he absolutely deserves it."