There was a time when Jack Bruce was synonymous with the bass guitar in rock history, when he was widely revered as the best there was on four strings. It is the instrument that nobody really glorifies, the invisible foundation of the groove, the low notes that underpin and hold things together, the liquid heart of the rhythm section. Rock tends to choose its heroes from the flamboyant top line of guitars and vocals. The bass was always basic, rock bottom, the instrument you played if you weren’t quite proficient enough for six strings. As Paul McCartney (the first world famous bassist in pop, but a very reluctant convert to the instrument) admitted: “nobody wanted to play bass.” But Jack did. He once told me he fell in love with the first one he ever saw, an old double bass in his school orchestra. The first time he touched it, he knew it was for him, so tactile and sensual, and, just as importantly, it was free to play (his working class parents couldn’t afford to buy him an instrument).