Sir Jackie Stewart retired from motor racing in 1973 aged 34, after eight years in Formula 1: 99 starts, 27 wins, three world titles – and most vitally he was still alive.

Stewart was his generation’s benchmark, he had nothing else to prove and never raced again. Sure, he could have returned, but in a deadly era he’d made a promise to his family, and with that famously heightened awareness of his own worth out of the cockpit, he didn’t need to. 

Most racing drivers find it tougher to walk away, especially those who perhaps didn’t achieve all they aimed for. But what’s harder is being forced to quit early, not on your own terms – usually because of injury.