Simpson was optimistic that he could finish high in the general classification, securing larger appearance fees from post-Tour criteriums.

[2][3] His plan was to either finish in the top three or wear the leader's yellow jersey; he had targeted three key stages, one of which included the thirteenth over Mont Ventoux, riding safe until the race reached the mountains.

[9][10][11][12] This could have been seen as a handicap, but Simpson was not guaranteed the leadership of his trade team, Peugeot-BP-Michelin, and would have to compete with Frenchman Roger Pingeon – the eventual winner of the 1967 Tour.

[14][15] As the race crossed the Alps, Simpson fell ill, across the Col du Galibier, with diarrhoea and stomach pains.

[18][19] In Marseille, on the evening of 12 July 1967 on stage 12, his personal manager, Daniel Dousset, put Simpson under pressure to produce good results.

[12][23] The thirteenth stage (13 July) of the 1967 Tour measured 211.5 km (131.4 mi); it started in Marseille, crossing Mont Ventoux (the "Giant of Provence") before finishing in Carpentras.

Dumas noted the warm temperature: "If the boys stick their nose in a 'topette' [bag of drugs] today, we could have a death on our hands".

Race commissaire (official) Jacques Lohmuller later confirmed to Hall that he also saw the incident and that Simpson was putting brandy in his bottle.

[25][n 2] As the race closed in on the summit of Ventoux, the peloton began to fracture, and for a while, Simpson managed to stay in the front group of elite riders.

Hall shouted for the other mechanic, Ken Ryall, to prise them loose and the pair laid the lifeless Simpson beside the road.

Hall and a nurse from the Tour's medical team took turns giving him mouth-to-mouth resuscitation before Dumas came with an oxygen mask.

[34][35][36] Approximately forty minutes after his collapse, a police helicopter took Simpson to nearby Avignon Hospital,[37][38] where he was pronounced dead at 5:40 p.m.[12][35][39] Dumas refused to sign a burial certificate and a poisons expert from Marseille was commissioned to conduct an autopsy.

He died in the saddle, slowly asphyxiated by intense effort in a heatwave after taking methylamphetamine drugs and alcoholic stimulants.

[55] The epitaph on Simpson's gravestone reads, "His body ached, his legs grew tired, but still he would not give in," taken from a card left by his brother, Harry, following his death.

[57] A granite memorial to Simpson stands on the spot where he collapsed and died on Ventoux, one kilometre east of the summit, with the words "Olympic medallist, world champion, British sporting ambassador.

[60] Over the years, Simpson's memorial slowly fell into disrepair and a new plinth was constructed, secured into the mountainside with steel rods.

[64] The Harworth and Bircotes Sports and Social Club has a small museum dedicated to Simpson, opened by Belgian cyclist Lucien Van Impe in August 2001.