Formula One champions Jenson Button and Lewis Hamilton hailed fellow Briton Dan Wheldon as a "true fighter" and an "inspirational" figure after the IndyCar driver was killed in a massive crash in Las Vegas.
Button recalled Wheldon, who died on Sunday at the age of 33, as being a star of the British karting circuit in the 1990s before going to win the Indianapolis 500 twice in the United States.
"I have so many good memories of racing with Dan in the early 90s, a true fighter," Button said on Twitter. "We've lost a legend in our sport but also a great guy ... I can't begin to imagine what his family are going through and my thoughts are with them at this very difficult time."
Wheldon, who was born in Buckinghamshire, a county just north of London, was also an inspiration to Hamilton following a successful junior career that saw him win eight British karting titles.
"Dan was a racer I'd followed throughout my career, as I often followed in his footsteps as we climbed the motor sport ladder in the UK," said Hamilton, Button's teammate at McLaren. "He was an extremely talented driver. As a British guy who not only went over to the States but who twice won the Indy 500, he was an inspirational guy, and someone that every racing driver looked up to with respect and admiration. This is a tragic loss at such a young age."