He also does a lot of mathematics, having read it as a student at Columbia. “I’m precise. I think in proportions. I play games with numbers and I proportionalise. I imagine we have now done 1/8th of our interview.” I check my watch. He even took a job as a maths teacher at one point, in the Seventies, despite being a world famous pop star. “I’d just got married and moved to Connecticut, and there...