De Cadenet finished on the podium at the French enduro in 1976 racing a self-run Lola-Cosworth T380 Group 6 machine together with Chris Craft, but he was probably best known for the line of prototypes that carried his name.
The Briton born to an officer in the French air services was the epitome of the plucky British privateer and a throwback to a bygone age even in the 1970s.
De Cadenet ran his cars from a tiny mews garage in central London, once towed one of his creations to Le Mans behind his 1928 Bentley Speed Six and even illicitly tested his latest prototype at high speed on the M4 motorway in the dead of night.
He competed at Le Mans 14 times between 1971 and 1986, seven of them in prototypes that can at least loosely be called DeCadenets - the space in his surname was generally dropped for his cars.
De Cadenet decided to build his own prototype when Ferrari wouldn’t sell him one.
He’d raced at Le Mans for the first time in 1971 driving one of the Italian manufacturer’s 512Ms for the Ecurie Francorchamps squad and made a bid to buy a new open-top 312PB for the following year.
When he was turned down, De Cadenet reasoned that the new three-litre PB was essentially a two-seater Formula 1 car and set about developing his own sportscar out of the Brabham-Cosworth BT33 he’d run under the Ecurie Evergeen banner in a couple of end-of-season grands prix for Craft in ’71.
Young Brabham designer Gordon Murray did the design on the ‘conversion’ in his spare time, resulting in the first DeCadenet LM, or the Duckhams Special as it was more commonly know in deference to a £500 sponsorship deal.
A car that raced at Le Mans three times was followed in 1975 by a Lola T380, which De Cadenet and his team started to develop and modify from the get-go.
It was already dubbed the DeCadenet Lola when he and Craft made it onto the podium in 1976 and the second true DeCad was created when the team commissioned a bespoke monocoque for its evolving machine.
De Cadenet's final car, the LM4, went to Le Mans in 1980 as one of the favourites after he and Desire Wilson had taken victory in the Monza and Silverstone World Championship for Makes rounds ahead of the French enduro.
Wilson crashed heavily in practice and wasn’t allowed to start because the timekeepers claimed she was outside the qualifying minimum, but the rebuilt car in the hands of De Cadenet and Frenchman Francois Migault went on to run as high as fourth.
A broken crossmember cost it an hour in the pits on Sunday morning, resulting in a seventh-place finish.
After one more attempt on Le Mans driving one of his own cars, De Cadenet subsequently raced for the British GRID and Charles Ivey Porsche squads, as well as making two starts with the local Courage Competition team.
De Cadenet went on to have a successful television career in the USA working for ESPN and Speed, while continuing to dabble in historics.
He began racing in 1966 at the wheel of an AC Ace, once claiming that he got started in motorsport because he thought it would be a good way to pick up girls, before graduating through Porsche 904, a Ferrari Dino 206S and then a Porsche 908.
De Cadenet had two brief involvements F1: after running the Brabham for Craft in a handful of races at the back end of 1971, he joined Graham Hill’s new F1 team for its debut season in 1973, overseeing the running of its Shadow-Cosworth DN1 before falling out with his new boss at the Monaco Grand Prix.