London - John Surtees, who won the 1964 Formula One championship to become the only man to win world titles on two and four wheels has died at the age of 83.
Besides winning the F1 title for Ferrari, Surtees also won 500cc motorcycle world titles in 1956, '58, '59 and '60.
Surtees' family said he died after being treated for an existing respiratory condition.
"We deeply mourn the loss of such an incredible, kind and loving man as well as celebrate his amazing life," it said. "He has set a very real example of someone who kept pushing himself at his peak and one who continued fighting until the very end."
Surtees is survived by his wife Jane and two daughters, Leonora and Edwina. A son, Henry, died in 2009.
Renowned for his courage and determination, Surtees will be remembered as one of the most gifted and versatile racers of all time.
He began his illustrious career on motorcycles in 1949 as a passenger for his father, a top sidecar racer, and went on to ride for Norton and MV Augusta. In addition to his four 500cc world titles he also won three 350cc world championships. He also became the first man to win the Senior TT on the Isle of Man in three consecutuve years.
He competed in more than 100 F1 Grands Prix, winning six, in a career which took him to Ferrari, Cooper, and Honda.
During the 1970s he also designed, built and raced his own Team Surtees F1, F2, and F5000 cars.
Motorsport was quick to pay tributes to Surtees.
Three-times F1 champion Lewis Hamilton said: "He was a legend of the sport, a lovely guy who did so much. It's a shock to everyone."
Ferrari driver Kimi Raikkonen, who won the 2007 F1 title with Ferrari, spoke fondly of Surtees.
"I met him a few times, he was very easy-going," Raikkonen said. "You could tell that he had passion for racing in his blood."
Ferrari posted a black and white picture of Surtees posing next to team founder Enzo Ferrari on Twitter, with the message: "John Surtees, Motorsport legend and 1964 World Champion with Ferrari, passed away. Our thoughts are with his family."
F1 driver Valtteri Bottas tweeted: "Sad news today. It was great to meet you legend. RIP John Surtees."
Damon Hill, the 1996 F1 champion, tweeted: "Such a lovely man. We have lost a true great motorsport legend. RIP John,"
There was also a message on the official MotoGP account which read: "Very sorry to hear that John Surtees, the only person to win both #MotoGP & #F1 World Championships, has passed away."