Nor did its design lack innovation. As Murray points out, “it was the first F1 car to use carbon-fibre in its tub and though it was also part aluminium, we used carbon-fibre in the car’s structure two years before McLaren.”

That, however, was not the BT49’s secret weapon, the reason which made the car the class of the F1 field and gave Brabham its first driver’s title since 1967. The ace up its elegant sleeve, says Murray, was downforce. “It just had more of it, more than any other car out there and it all came from the ground effect. We ran the car with no front wing at all and scarcely any at the back. It all came from under the car and it generated more pure downforce, I think, even than the Williams. When we had to run a flat bottom, we lost two-thirds of the downforce in an instant.”

Its engineering simplicity did, however, play a key role. “It was the most reliable car of its era. In Nelson’s championship year he never failed to finish through mechanical failure.” The books support this: fifteen starts, ten finishes, four accidents and one mechanical failure when his engine blew at Monza on the last lap relegating him to sixth.

The elegance and simplicity Murray refers to is not simply beneath the skin. To my eyes, the Lotus 79 is the only one of its contemporaries with a claim to greater beauty. It’s at its best seen from dead head-on, where the downward curve of its gently sloping side pods have elements of Concorde’s wing profile. The nose sharpens to a defiant point, there is nothing to interfere with the airflow over the body save the mirrors and driver’s head while the Parmalat livery is one of the smartest of all.

Beautiful, however, does not mean big in this case. The BT49 was the first GP car Murray had designed which was unable to accommodate his six foot four frame. “Our big drivers like Watson had all left the team so I chopped three or four inches.out of the monocoque. How on earth did you get in?”

By removing the seat and bodywork that’s how. The elegant body is, in fact, all one panel and lifts off easily. I could then just about cram myself into the tub, rear seat-belt mounting points dug deep into my back and strap myself in before the bodywork was replaced. If I’d had an accident or had to get out of the car in a hurry for any reason at all I would have stood no chance at all. Someone plugged in a starter and, with a whoop and a bang, eye-wateringly loud through a helmet, balaclava and ear-plugs, the Cosworth fired up.

This DFV sounds different to most hammering around the track, reflecting its extreme state of tune. It’s note is more melodic, smoother and exciting than usual. Giles cautions me never to let it run below 6000rpm, suggests I shift at 10,500rpm to give myself a little room for error (he takes it to 11,200rpm) and advises that it only really gets going above 8500rpm.

The first couple of laps were easy enough. The Hewland six speed box is one of the best I’ve used, the tyres were already warm and my only interest was making sure I found my way around the track without getting in anyone’s way. Two thoughts occurred: first, it was only with the greatest effort that I could lift my right foot sufficiently for it to disengage from the accelerator and move across to the brake and, secondly, I was not sure I had ever been more uncomfortable in my life.

What I had hoped would be one of the great experiences was fast turning into a misery and much as I would like to blame anyone else, the real reason was me. I simply did not fit this car and should have given up the struggle, saving myself a great deal of pain and making the day of at least two people back in the pits.

It was only the knowledge that the experience would remain long after the bruises had faded that kept me out there. On lap three, I started to drive the Brabham rather faster and, as the rev-counter swept past 8500rpm, so all thoughts of how I had got myself into this situation in the first place vanished. Funnily enough, it didn’t seem to hurt any more either.

Suddenly I was busy, more busy than I remember ever being in a car. In this car, there are no straights as such. Straights are where you relax, change gear every so often, check instruments and think about where the traffic is, how many laps remain and such like; straights are called straights because they are where you straighten up those affairs left untended while your concentration is required in the corners.

Not in this car; coming out of Coppice in third (I expect the truly brave use at least fourth) the usually long stretch to the start of the Melbourne loop seemed to have gone missing, absorbed into a frenzy of gearshifts, tachometer needle flicking into five figures time and again and, more than anything else, utter determination to arrive in the braking area in good shape to lose three gears and 100mph in time to angle into the Esses. I was surprised to feel the Brabham under and over-steer in the hairpins that led back to the pit-straight, feeling restless but not uncomfortable on departure from the Melbourne hairpin, and using every inch of track at Goddard, simply to get around the corner. Giles had noticed as much when he was driving and suggested it probably had more to do with a quirky differential than anything I might be doing. In the faster corners, despite no longer boasting the skirts it once used to such effect, I got nowhere near to the limit.

I returned the Brabham to its owner and pulled up outside the pit and thought back to this car’s finest hour. It coincided with one of Grand Prix racing’s darkest. The 1982 Canadian GP will only ever be remembered for the death of Riccardo Paletti, coming scarcely a month after the loss of Gilles Villeneuve. It marked a water-shed in attitudes to on-track loss of life and, to date, there have been just three deaths in F1, one in testing, one in practice and one during a race.

Brabham had used a mix of DFV and BMW turbo power all season, the latter having hitherto finished just one race to date. Piquet had a 1.5-litre BT50, Patrese this BT49D. Nelson led from lap nine to win, Riccardo running home to an unchallenged second. It was BMW’s first Grand Prix win and, as it transpired, Brabham’s final 1-2.

Driving it was an experience you only appreciate once it’s over. On the track, there was simply too much to do to enjoy it at the time; if you knock back a drink without pausing for breath, you only taste it once it’s gone down; so it proved with the Brabham. Sitting in the pit, waiting for the bodywork to be removed to allow my escape, I was both aghast and relieved the experience was behind me. Driving back to London, I started to appreciate the extraordinary privilege that had been afforded me and the generosity shown to and trust placed in me by its owner. Some months later, I now know this day that had started so badly will be one I will cherish for years to come. All in all, I would not have missed it for anything.

Our sincere thanks go to Ian Giles for trusting us with his car and to Thoroughbred Grand Prix (01451 810855) for providing the track time.