At the head will ride Joanne Simpson, the daughter of Tommy Simpson, who was four when her father died within sight of the summit on a blistering afternoon 30 years ago today. At her side, Barry Hoban, her stepfather, who was a member of the British team led by Simpson on that Tour de France. In the car behind will be Helen Hoban, Tommy's widow.
Simpson was lifted from his bike by helpers and fans late in the afternoon of 13 July 1967, on the Tour's 13th stage. He was given mouth-to-mouth resuscitation by the Tour doctor but died shortly after being airlifted to hospital. The press room was given the news at 5.40 by the race organiser, Felix Levitan, and the cortege today will rendezvous at the same hour, adding a wreath to the hats, jerseys and paraphernalia which are laid by cycling aficionados each summer at the foot of the stark monument to Simpson's death.
The route of this year's Tour does not go up Mont Ventoux, but tributes will be paid to both Simpson and to Fabio Casartelli, the Motorola rider who was killed on a mountain descent on the 1995 Tour.
Simpson's death, at the age of 29, shocked the world of cycling, not least because the trace of amphetamines found in his blood revealed the darker side of the sport's prevailing culture. He was a popular figure on the continent, the first English rider to lead the Tour - in 1962 after a superb ride over the Pyrenees - and a master of the dashing breakaway.
Simpson's finest hour came in Spain, in 1965, when, in heavy rain, he won the world road-race championships. Soon after, he won the Tour of Lombardy, but it was a train of bad luck through the following year which made Simpson so desperate to do well on the 1967 Tour. "His ambition knew no bounds and he ended up paying the price for it," as Eddie Merckx said.
Earlier this year, a memorial stone was unveiled in Simpson's home town of Harworth in Nottinghamshire. It read simply: "In memory of a Harworth cyclist, Tom Simpson, Olympic medallist, classics winner, world champion... who died in the 1967 Tour de France."