Ahead of a BBC adaptation of her novel, the Booker-winning author reflects on failure, creative alchemy – and being consumed by her closeted seventysomething hero

I spend a lot of my life being other people, spending years inside the lives of my fictional protagonists, and, when the creative alchemy is going well, it is intensely satisfying. It’s not that I can’t bear being myself, but to be honest, I find other people much more interesting. Creating characters and unravelling their stories is an invigorating and unpredictable adventure into the unknown. It might be daunting sometimes, and I’m never sure of the outcome, but when I’m in the zone, it’s one helluva ride.

When I wrote my 2013 novel, Mr Loverman, I felt deliciously consumed by my 74-year-old Caribbean protagonist, Barrington Jedidiah Walker Esq. He arrived easily – no birthing pains – and when my husband came home in the evenings, I’d inhabited him so deeply, I found myself unwittingly talking to him in Barrington’s Antiguan accent. “Y’all right, spar?” I’d ask him, the boundaries between character and creator momentarily blurred, much to my husband’s amusement.