Blake, a 25-1 outsider to win, is a Goldsmiths College music graduate who was previously nominated for the Mercury for his self-titled debut album which he recorded at his home in New Cross, south east London.
Accepting his award, he said it was "amazing" to be in the running for an award with chart veteran David Bowie.
Asked what he would spend the money on, he said: "I'll make sure it goes to some good use".
He added: "This is the first award I've ever won apart from a tennis trophy which I won when I was about 12-years-old at my school and I'll hold them in equal esteem".
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Video taken in Soho Square shows sparks flying into the air as the men cut through a lock on the Ducati bike.
Salim Coulter was shot in the head as he got into a friend's car opposite a restaurant on Waltham Road.
At the mention of her name, the Kitty Hart-Moxon stood up and gave a brief wave to the chamber from the gallery.