The 1986 season was memorable in many ways for McLaren, not least because Alain Prost won his second straight world championship – the first time that a driver had taken back-to-back titles since Jack Brabham in 1959 and 60. But in that year’s Italian Grand Prix at Monza, Alain must have wondered whether the Gods were against him as he found himself rewarded for half an hour’s high speed slog round the famous Milanese circuit by being black flagged out of the race.

Truth be told, Monza ’86 was one of Prost’s very finest races and proof positive, if it was at all needed, that he could overtake in high speed traffic just as well as anybody else on the grid. And he was also well capable of dealing with whatever team-mate was signed to drive alongside him in the McLaren squad.

In 1984 and 85 he had been partnered with Niki Lauda and quickly managed to gain the upper hand in terms of pure speed over the seasoned Austrian ace. Then in 1986, after Lauda retired from driving for good, he found fresh rivalry from Keke Rosberg, the 1982 world champion who was joining McLaren from Williams. Rosberg freely admitted that he found it difficult to integrate into the McLaren squad, not only because he felt that Prost had his feet firmly planted beneath the table, but because he could never dial out the incipient understeer which he felt compromised the performance of that year’s McLaren MP4/2C.  Prost, by contrast, seemed well able to live with this aspect of the car’s behaviour.

Not that this proved to be a significant factor behind the unfolding McLaren drama at the Italian Grand Prix. This race, perhaps uniquely, began with neither of its front row qualifiers able to take their positions on the starting grid, both pole man Teo Fabi’s Benetton-BMW  and Prost’s McLaren-TAG encountering technical problems before the start. Fabi stalled on the final parade lap while Prost’s car developed an alternator problem, so Alain switched to the spare car and duly took the start from the pit lane, just the sort of frenzied pressure a driver could do without during the build-up to an F1 start.

While the Williams-Hondas of Nigel Mansell and Nelson Piquet, together with Michele Alboreto’s Ferrari, all took turns at leading the race, Prost came hurtling through from dead last to sixth place by the time 18 laps had been completed. However, by this stage – more than 30 minutes into the race – the stewards had decided that Alain had switched to the spare McLaren a scant 5sec too late after the green flag had been shown to despatch the field on its parade lap. Out came the black flag and Prost was disqualified.

Taken at face value, it might have seemed remarkable that Alain had been allowed to risk his neck for no reward for such a long time – even taking time for a pit stop to change the nose section which had started to collapse – although Ron Dennis had spent much of the race up to that point attempting to prevail on the stewards to let his driver run through to the finish and to debate the matter afterwards.

It was no consolation that Prost’s TAG turbo V6 expired expensively on lap 28 just as he was about to return to the pit lane. Feisty as ever, Prost did not mince his words when it came to expressing his thoughts about developments, directing a robust broadside at the sport’s governing body – only to be rewarded with a $6000 fine for his unwelcome candour.

In the end, Piquet and Mansell scored a 1-2 victory at Monza with Stefan Johansson’s Ferrari third and Rosberg in the other McLaren in fourth place. Yet although it had been a highly disappointing race for McLaren, Prost had once again showcased his outstanding quality as a driver, something which his detractors unfathomably seem minded to criticise even to this day.