Why do so many of us dedicate countless Sundays to watching cars drive around in circles? I've never come up with a single satisfactory answer, though there have been moments where it's all come into focus: like how on one sodden late-September morning I traipsed up to Brands Hatch's Grand Prix loop and saw another cagoule-sporting enthusiast camping out under one of the dripping trees. "Why on earth do we do this?", he asked, before he was interrupted by the urgent swoosh of a Lotus Cortina, a petite blur of white and green fury as it launched itself up from the kerbs of Dingle Dell corner. We looked at each other in a moment of silent satisfaction as the answer so perfectly presented itself.