The award is presented for the year's best British or Irish album.
"Well, I lost the bet," the BBC quoted the 25-year-old singer-songwriter as joking after he beat out Laura Mvula, David Bowie and Arctic Monkeys for the prize.
Describing his mood as "jubilant and confused," Blake said, "This is the first award I've ever won apart from a tennis trophy I won when I was 12."
The BBC said judges called Blake's record "inventive, poetic and poignant."
Swim Week Miami Beach 2014 [PHOTOS]