Bob Fernley, the Briton who for a decade served as deputy principal of the former Force India Formula One team owned by Vijay Mallya, died on Friday at the age of 70.
Formula One and former colleagues confirmed the death.
A close associate of Mallya, Fernley was the Indian businessman's representative at the racetrack and acted as a go-between.
"Bob always would tell us what Vijay would want in certain situations, which was very helpful," Otmar Szafnauer, the former Force India chief operating officer, told motorsport.com on Friday.
"He allowed the rest of the organisation to focus on the job at hand of racing, getting the car better, hiring the people, and he would deal with all the politics," added Szafnauer, the current Alpine team principal.
Force India went into administration in 2018 and its assets were sold to Canadian billionaire Lawrence Stroll with the Silverstone-based team competing first as Racing Point and now as high-flying Aston Martin.
Fernley subsequently ran McLaren's IndyCar project and was then head of the governing FIA's single-seater commission from 2020-22, taking over from current Formula One chief executive Stefano Domenicali.
"He was such an important part of Formula One and his love and passion for the sport will live forever," said the Italian on Twitter.
Mallya, who remains in Britain despite Indian efforts to extradite him following the collapse of his defunct Kingfisher Airlines, said he was "totally devastated at the loss of my best buddy of 45 years".