A bit like the freemasons, every Top Gear event has a different handshake. A moment that not only tells you it’s underway, but that everything will be alright.

This year’s happened like this. We all arrived at night to a quiet hotel, had a small bite to eat, drank absolutely no beer and went to bed early. The next morning we shuttled down to the paddock. Which we found entirely deserted. Eventually, one of our number remembered he’d been given some keys, labelled 31 to 40. Pit garage 31: empty. Pit garage 32: empty. Pit garage 33: radios (shouldn’t bother, all we do is lose them). Pit garage 34: snacks (wot no Quavers?) and not nearly enough water. Pit garage 35: drums labelled Repsol 100oct.

By this stage anticipation and concern are building in equal measure. Five garages down, five to go, and no cars yet.

And then comes pit garage 36. Soft morning light streams in and conspires to fall perfectly on the Porsche 935, lifted on its axle stands. It’s a perfect sight. One of this year’s rarest and most exciting cars, parked up and waiting quietly, patiently. No need to investigate further right now, just stop and drink this in.

We usually call this Performance Car of the Year – PCOTY for short. On other occasions it’s been Speed Week. But this year it’s TG24 and the format is slightly different. When we sit down to start planning this each year we try to imagine what the ultimate track day of this year’s greatest driver’s cars would look like, what it would include. This year we stripped the track day concept back so far we ended up asking ourselves, ‘Day? Why only day? What about night?’. And 10 seconds after that we were planning Le Mans.

But, aside from Le Mans – run primarily on public roads – where could we go that would allow us to run for 24 hours? And – no small matter this – had no noise restrictions. Step forward the awesome Portimao circuit in southern Portugal. Complete with southern Portuguese weather: perfect cloudless days pursued by moonlight and stars. Ah, night time, when the mercury had the decency to drop below 30 degrees and our skin stopped blistering.