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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A round the world yacht race set off from London today on a year long journey which will see them circumnavigation the globe.
The shortlist for the ugliest buildings in the country has been finalised with four of them coming from London.
Hundreds of thousands of people turned out for the Notting Hill Carnival today with the weather just managing to hold off.