- May 5 down the years
Underweight Prost disqualified
The San Marino Grand Prix ended in farce when Alain Prost was disqualified two hours after crossing the finishing line in first place after his car, which ran out of fuel on the warm-down lap, was found to be two kilos underweight. Ayrton Senna's Lotus and then Stefan Johansson's Ferrari had also run out of petrol while leading, while Nelson Piquet appeared set for a podium spot until he too spluttered to a halt on the final lap. The stewards eventually awarded the win to Elio de Angelis - who by then was at the airport - with Thierry Boutsen second, even though he had to push his car to the finish after also running out of fuel. Other teams protested as Boutsen had not pushed his Arrow fully over the line.
Achille Varzi recorded his third win at the Tunis Grand Prix, his first for Auto Union, although for a time he was entered as an independent after a row over prize money - he wanted it paid in lire as the Nazis had imposed strict limits on the amount of currency that could be taken out of Germany. Varzi led throughout and finished almost four minutes ahead of Jean-Pierre Wimille's Bugatti.
The Targa Florio was a head-to-head battle between Bugatti and Alfa, and Albert Divo led from the third lap to record Bugatti's fifth successive victory. Among the participants was Madame Juneck, a pioneer lady driver, who even briefly held the lead in her black-and-yellow Bugatti.
A day to forget for Thomas Scheckter, son of former world champion Jody, who was sacked from his job as a Jaguar test driver after being found kerb crawling in Milton Keynes.
As Prost's eponymous team collapsed about his ears, 12 of its cars were sold at auction at the Palais de Congres in Paris for US$900,000.