In May Mick Jagger posted an Instagram video of him practising his famous, snake-hipped dance moves a mere month after having heart surgery. The message was clear: it was back to business as usual for the Rolling Stones.

An American tour postponed in April to allow the singer to receive a replacement heart valve was under way by June, with the 75-year-old fitness fanatic as energetic as ever. His bandmates called him superhuman.

Tom Jones, 79. His recent show at the Royal Hospital received a five-star review in The Times BBC

What the fans didn’t see was a cardiologist sitting at the side of the stage on the opening night who, due in part to insurance demands, has been present at every performance since. In the 1960s the Stones took their dealers on tour. These days it’s doctors and dieticians, and the pills