Baker was born in 1939 in Lewisham, south London, and grew up amid the blitz; his father was killed in action in 1943. He began drumming in his mid-teens, remembering in 2009: “I’d never sat behind a kit before, but I sat down – and I could play! One of the musicians turned round and said, ‘Bloody hell, we’ve got a drummer’, and I thought, ‘Bloody hell, I’m a drummer!”