You climb in through the left hand door to avoid becoming tangled with the gearlever, sited to the right of the central driving seat. It’s not exactly what you’d call dignified for more conventionally proportioned drivers than I and is not helped by the huge steel roll cage upon which the rule book insists but which has little greater effect than needlessly adding weight to the already considerably stronger carbon-fibre tub. Even so, the effort is worth it once on board, it is a brilliantly comfortable racing car.

I have its designer, Gordon Murray, to thank for that. It was Gordon who determined that any road car he designed (the F1 was his second after the Light Car Company’s extraordinary Rocket) should at least accommodate his 6ft 4in frame and, as he will tell anyone who asks, he never designed the F1 to be a racing car. The result is more headroom than you could hope for and titanium pedals which meet your feet precisely where you hope. Better, the suede rimmed steering wheel is unfashionably large and considerably easier to control as a result

Pumps and ignition on, hit the starter and bang, the BMW V12 is alive. It has 6.1-litres, variable valve timing and the best part of 500lb ft of torque. Its power output is limited by its restrictors. Murray says that, without them, an all day and all night 800bhp would be childishly easy to provide.

First gear clunks easily into place. Early GTRs had problems with their gearboxes and this one was past its best but with a gentle syncromesh (Murray designed it this way out of a concern that some private entrants might damage a straight-cut dog box during a race) and an entirely reasonable clutch, setting off is easy.

You would be pressed to find another racing car of similar performance that was so easy to drive slowly. Rowed along on an ocean of torque from the ever-obliging V12, gears slipping considerately into place, so long as you took care not to hoof the throttle too hard at the exit of each corner, you could drive the McLaren around the track at Ford Escort speed until the tank ran dry. There’s no shunt in the driveline and the engine will pull like a locomotive from just 2000rpm. The suspension bangs about a bit over the bumps but no more than you’d expect from a road-derived system that’s had all its rubber bushing removed but, that apart, the F1 GTR is civility itself.

The problems arrive when you try to drive it in a manner at least approaching that for which it was designed. On this cold day at this damp, unfamiliar track, it’s a job in itself just to coax enough heat into the slicks to make them work properly. You must push harder than you want on the cold rubber as, paradoxically, the danger inherent in this is the only route to the safety brought by warmed tyres. At least the steel brakes don’t seem to mind the conditions.

Your ally, through all of this, is the engine. To be honest, for all its monstrous power and electrifying throttle response, it feels like it is, a ludicrously powerful and shatteringly noisy road car engine, not a purpose-built racing unit. This is an entirely positive facet to its character. With no turbos to catch you napping with a flood of uninvited boost and a powerband that, while notably stronger above 4500rpm, will still slog from 2000-7400rpm without protest, you can be more relaxed with your gear ratios; and every time you touch the throttle, the consequent response is neither more nor less than you envisaged. Blundell’s advice, just before the door slammed, to keep the gears high and not to bother straying beyond peak power at 7000rpm, starts to make compelling sense.

It is about now you realise how quick this car is. While a properly prepared racing Ferrari F40 was probably a match for it at some circuits and perhaps potentially quicker over a single lap, few were able to extract the most from it and those that did rarely continued to do so for long before some mechanical failure stopped play. It won just one race all season. The amazing side of the McLaren’s performance is as much its relentless nature as its pure speed. By the time I drove it, the season was six races old and not one of the six F1s had retired with an engine failure. And even after Le Mans, the V12’s race record would continue without blemish.

For now though, I am enjoying acceleration that spans neatly the space that exists between simple fury and God-help-me mania. You never stay in second gear for long enough to enjoy its redoubtable punch and, besides, you’re concentrating too much on timing the change to soak up the ride. Third is a marvellously imperious blast while it lasts but it’s only when you tug the lever through its short throw back into fourth that the searing surge stays around for long enough to savour.

And then the noise, hitherto off-loaded into that part of your brain which looks after non-critical items while the rest is working overtime, starts to register. You might think a V12 engine displacing rather more than 6-litres would possess a bass roar. In fact, it pitches its voice higher into an initial growl, moving through an eerie wail as it builds to its an intense shriek as musical as it is startlingly loud inside the cabin.

Confidence grows as we hurtle around Pembrey. Scratch what I said earlier about not knowing the track; six years before I had completed a dozen or so laps here in a Vauxhall Nova and while I had not been relying upon the experience to remind me of a thing, I find the basic layout of the circuit has a certain familiarity. Better still, the McLaren behaves itself impeccably given the uneasy friction existing between its tyres and the damp track and my behind-the-wheel blunderings.

Best of all, it’s neither a particularly difficult nor an exhausting car to drive. Just like the road car, the steering is unexpectantly light and retains sensible gearing. As efforts and temperatures increase, so its initial kickback becomes rather more welcome feedback and if it still tramlines hard under heavy braking, the fundamental stability of the car is never in doubt, even when it lets me know the nose is starting to push gently away from the apexes of slower corners.

Alas, as is almost always the case with such brief exercises, there are not enough laps available and by the time the pit board summoned me back to the paddock I had yet to feel entirely at home in the cockpit of the F1.

Looking back at it now, I wonder how much of that could be attributed to the car and its nature and how much to the circumstances in which I found it. It could scarcely have done much more to help: it proved comfortable, easy enough to drive and, for all its speed, abidingly tolerant of the conditions and its driver.

What I liked most about it, however, was how much like the McLaren road car it felt. And while the McLaren F1 was perhaps as esoteric and unreachable as road cars come, that was nevertheless the purpose for which it was designed. And as a person who still believes that a proper sports-racing car should only be a set of tyres, silencers and number-plates away from the public road, that was important to me then.

What I could not have known at the time, is the car the McLaren F1 racer would become, winning back to back championships in ’95 and ’96 and only finally succumbing in ’97 to the might of a Mercedes that was not simply three years younger but also designed to an entirely different brief: that of a purpose-built racing car.

Even so, its place among the very greatest of Britain’s sports cars is assured. Straight out of the box it beat the best that Porsche and Ferrari could muster and showed the world that racing cars bred from road cars with recognisable shapes need not mean the end of enjoyable sportscar racing. On the contrary, after the excesses of the last days of Group C, these sports cars were responsible for a massive resurgence of interest in the breed.

Sadly, however, the McLaren F1 GTR may well prove to have been that little bit too good. It was in its efforts to beat the McLaren that Porsche decided to ignore the spirit of the rules and build a pure racing car. Mercedes did the same to beat the Porsche and now, it would seem, BMW has asked Williams to build a car to beat the Mercedes. Sports car racing this year will be a battle between huge manufacturers fielding cars designed to race first and travel on the road a very distant second.

The real worry is that costs will escalate so much that the private teams will no longer afford to be able to race for the scraps left by the factories, making interest wane as surely as it did at the beginning of the decade and the very manufacturers whose cars caused this sea-change in GT racing will themselves no longer be able to justify the expense of fighting battles that ever fewer people want to watch. Having regained all it lost just a few years ago, I believe sports car racing’s long term future once more to be in jeopardy and while the McLaren F1 can stand proud as the best of those who obeyed the spirit as well as the letter of the law, they don’t hand out points for moral victories.

McLarens at Le Mans 1995

Seven F1s went to Le Mans, of the five that finished all bar one was in the top five. This despite it raining for 16 hours and the F1 GTR never having turned a wheel in the wet. In the race, Ray Bellm’s car lost 30 minutes repairing accident damage. It finally crossed the line in fourth place, less than 30 minutes behind the eventual winner…