It's been a long Saturday at Le Mans, and we hardly notice as we move past one-third distance at 11pm and then into Sunday. The cars are sporting illuminated numbers so we can see who's who, and leader lights tell us which racers are in contention for each class using their respective colours of red (LMP1), blue (LMP2), green (GTE Pro) and orange (GTE Am): one light for first, two for second, three for third.

In the darker corners of the circuit where you can't even make out the blacktop, dazzling headlights moving towards you flick between stability and violent side-to-side sweeps, then comes the noise - even more compelling in the sense-deprived darkness - and then the red rear lights dance away. Sneaking a peak at the drivers' view via the big screens, you get an inkling of what they're going through: a combination between night-time autobahn speeds with city-centre proximity. Some endure this intensity for more than three hours at a time.