Fitness for purpose. You’ll have read the words on these pages before and you’ll read them again. The phrase is the underlying criterion by which we judge all cars.

In most cases, a car must fulfil many purposes. The McLaren P1, though, has just one, as defined by its maker itself: the P1, says McLaren, must be the best driver’s car in the world.

Not necessarily the fastest, the loudest, the most technically dazzling, the lightest or the most powerful. Just the best – the most rewarding to drive on the road and, probably more frequently, on a circuit.

Given that cars like the Ford GT40, Caterham Seven and McLaren’s own F1 exist – not to mention the recent Porsche 918 Spyder and LaFerrari – that’s no small order, but McLaren is used to setting itself immodest goals and modestly delivering them.

McLaren has been making carbonfibre-chassised racing cars since the MP4/1 of 1981 and has made only composite cars since. Its first road car (M6GT prototype aside) was the F1 of 1993.

The F1 also proved well engineered enough to win the 1995 Le Mans 24 Hours, in the same year that McLaren F1 forged links with Mercedes-Benz. That led to the creation of the Mercedes-Benz SLR McLaren in 2003, a car that ultimately satisfied the goals of neither company. The 12C, 650S and P1 are pure McLaren, and it shows.

From a standing start, the Woking-based company is now the world’s most prolific producer of carbonfibre-chassised road cars, a material that also underpinned the McLaren F1.

And just as was the case with the F1, we were the first to produce independent performance figures.