The World Endurance Championship is, by any measure, on an upward curve.

Saturday's Spa 6 Hours attracted a crowd of more than 50,000, up 8000 on the 2014 running of the event. With Nissan about to join the fray to make it four works marques in LMP1, interest is demonstrably increasing among manufacturers as well.

The Spa race was a great one, a close battle between Audi and Porsche, with an eventual winning margin of only 13 seconds in an event uninterrupted by safety cars. By the standards of endurance racing, that's spectacularly close.