A Girl Is A Half-Formed Thing by Eimear McBride. Congratulations to her!
I feel both glad, because the novel is very good, and sad, because my two outstanding contenders from the longlist didn't even make it to the shortlist: The Luminaries by Eleanor Catton and All The Birds, Singing by Evie Wyld. Overall, I'd have loved to see Wyld take it. But this year was an exceptionally strong one, and McBride is certainly a worthy winner.
(Also, for the FIRST TIME EVER I predicted the winner correctly! I'm extremely excited about this because it will probably never happen again.)