To offset the power disparity to the powerful turbo cars of Renault and Ferrari, the top British teams had unilaterally decided it was ok to re-interpret the part of the weight regulation which stipulated that fluids could be replenished post-race before weighing. That courtesy was there in order to prevent embarrassing disqualifications for being a couple of kilos under. Typically, around 10kg of oil and water would be added, which was usually enough to cover any small miscalculations at a time when it wasn’t possible to monitor everything as closely as today. That courtesy was then abused by Lotus, Brabham, Williams and McLaren – and probably others too. They would have water tanks for their ‘water-cooled brakes’. Pipes from the tank could spray the water vaguely in the direction of the brakes but in reality the tanks were always empty. Until the end of the race when they’d be filled with up to 40kg of water.

It was an outrageous ruse but the stakes were high. A couple of years earlier the governing body president Jean Marie Balestre had gone to war with Bernie Ecclestone, boss of FOCA (Formula One Constructors’ Association, which represented about 70% of the grid) over who controlled the sport. Balestre had regulated against the FOCA teams in his limiting of ground effect, the mastery of which had been a key weapon of the normally-aspirated British teams in combating the turbos. The FOCA teams had been fighting for their very existence as Balestre hoped to encourage more manufacturer teams to swamp the FOCA camp and their by-now puny DFV motors, so reducing Ecclestone’s power. But Balestre and Ecclestone had reached a compromise agreement after the FOCA-only 1981 South African Grand Prix. The governing body would remain in control of the regulations, the commercial rights would be leased out to FOCA. The birth of the Concorde Agreement. It was an uneasy truce but it had pulled F1 back from the brink.

But the FOCA teams still had the problem of the increasingly powerful turbos. It had taken over a decade of development to get the DFV from its original 400bhp to around 500. The turbos were often making such progress in half-a-season, now that their boost and ignition could be electronically controlled. Furthermore, Renault and Ferrari were now fielding cars with aerodynamics as good as the best FOCA cars. Weight was the only remaining competitive battleground for the DFV-engined FOCA teams. Their cars were intrinsically lighter, without all the extra plumbing and cooling capacity needed for a turbo. So they could easily be built to way below the 580kg minimum weight. The turbo cars could not. The justification given for the water tank cheat was that the regulations did not specifically forbid it.

Understandably outraged at such a spurious and cynical justification, Renault had protested the cars of Piquet and Rosberg in Brazil. At the next race, in Long Beach, Ferrari, using the same reasoning as the FOCA teams, claimed that the regulations, while stipulating the dimensions of the rear wing, did not say how many rear wings you could have on the car. Villeneuve finished third in a Ferrari with two rear wings mounted side-by-side, extending as far out as the tyre sidewalls. He was disqualified.

Renault team manager Jean Sage backed up Ferrari’s position in their reaction to how spurious the water-cooling ruse was. “Yes, the regulations do not say that you cannot win a race by machine-gunning your opponents out of the race either. But it’s not something we’d expect to be accepted.”

It was becoming petty. But it became something far bigger when it was announced after Long Beach that the Brabham and Williams appeals against their Brazil disqualifications stood and Renault’s protest was upheld. They were out, with the official win going to Alain Prost’s Renault.

At this, the FOCA teams revolted. They would not attend the following San Marino Grand Prix at Imola. The race took place with just 14 cars. Balestre needed to do something. Formula 1 was grinding to a halt. His loyalties were divided. Ferrari and Renault had always sided with the governing body in its struggles against Ecclestone, but in ’81 he’d reached an accommodation with Bernie about the big picture and the Concorde Agreement was the result. Besides, only Ferrari and Renault were fielding competitive turbos. The mass arrival of other automotives had not really happened. He needed to find a way of bringing the outrageous brake-cooling ruse to an end while giving Ecclestone and the other FOCA teams some compensating changes they could live with.

At a convention in Casablanca with all the interested parties between the San Marino and Belgian Grands Prix, Balestre announced that for the following year the minimum weight would be reduced to 550kg (theoretically helping the DFV cars maintain a weight advantage over the turbos) but with immediate effect the top-up of fluids could be no more than 2% of the total weight (11.6kg). The Brazil exclusions stood. Ferrari had agreed to drop its appeal of the Villeneuve Long Beach exclusion. But there would be a progressively reduced fuel limit over the next two years, getting down to 200 litres by 1984 (which would again help the FOCA teams as the turbos would need to be detuned to meet this requirement). Peace had broken out and the first race of this new era would be the Belgian Grand Prix in Zolder.

In the meantime the circumstances of Imola had triggered the showboating arrangement between the Ferrari and Renault drivers there in an attempt at providing a show. This in turn had led Didier Pironi to steal the win from Ferrari team mate Villeneuve, who had declared war in the aftermath. He was in a tormented state of mind as he crashed fatally in Zolder, trying to beat Pironi’s time. The troubled times had inadvertently put the pieces of that tragic tale into place.

But there was still a race to be run. The Renaults of Prost and Rene Arnoux were on the front row, with Rosberg and Lauda on row two. Lauda’s McLaren team mate John Watson had qualified only 10th but figured he’d found a perfect tyre combination for the track’s surface; two hards on the outside, softs on the inside. Lauda had opted for softs all-round. The Renaults were out after a few laps, leaving Rosberg leading from Lauda.

Watson was doing what would become one of his trademark charges through the field and with his tyres holding up far better than Lauda’s, passed him for second with 22 laps to go. Rosberg, struggling with tyres and brakes, locked up on the penultimate lap and Watson was through for a great, beautifully-judged victory. One which history tends to forget, overshadowed by what had happened the day before.

So as the top three finishers were taken to the weighbridge, with their permitted 2% fluid replenishment, there were some anxious moments. There was obviously going to be zero tolerance of weight infractions in the first race of this new era. Watson’s car was a scant 1kg over the minimum. Rosberg’s was 11kg over, Williams clearly playing safe. Lauda’s was 2kg under and therefore excluded, giving the official third place to Eddie Cheever’s Ligier.

There was a minor postscript. McLaren appealed the exclusion but not with any real hope of success. It would be heard much later in the season. So much later that actually, heading into the season finale at Las Vegas, it was potentially very problematic for F1. Rosberg led on 42 points, with Watson on 33. With a 9-6-4-3-2-1 scoring system for the top six, Lauda’s score of 30 points meant he could not win the title even if he won and neither Rosberg nor Watson scored. Unless, of course, he later got his four points from Zolder back. In which case Lauda could potentially be on 43 points… Thankfully, it didn’t matter in the end as Lauda retired from sixth with no oil pressure and Rosberg sealed the title with a fifth place.