Five-time Le Mans podium finisher Richard Westbrook has called time on a career in which he was a factory driver with Porsche, General Motors, BMW, Aston Martin and Ford.
The 49-year-old Briton has announced that last weekend's Petit Le Mans IMSA SportsCar Championship finale at Road Atlanta was his last race as a professional driver.
Westbrook's decision to retire brings the curtain down on a career that included back-to-back Porsche Supercup titles in 2006-07 and class victories in the Sebring 12 Hours and Daytona 24 Hours enduros in 2013 and 2018 respectively.
As well as third-place finishes overall with Glickenhaus and Cadillac at the Le Mans 24 Hours in 2022 and '23, he notched up a trio of class podiums at the Circuit de la Sarthe with Porsche, Ford and Aston Martin.
Westbrook explained the time was right to call time on his career, despite having a year left to run on his contract with the JDC-Miller MotorSports Porsche GTP team with which he has raced in IMSA this season.
"You can't do it forever and at some point you have to be honest with yourself, say you've had a good run and pass on the baton," Westbrook told Motorsport.com.
"This was the first season that I have felt like that: my performances were still there, but the enjoyment factor had gone a bit. I wasn't so excited about getting in the car as I had been in the past, and if that's the case, you have to question whether you should be doing it.
"I'm happy with my career and the way it has ended: I probably wasn't going to achieve a lot more and it has been my decision to stop."
Westbrook said that his biggest achievement was racing for 23 seasons after he started competing again following six years of inactivity after his single-seater career stalled in Formula 3 in 1996.
"I have to pinch myself sometimes what has happened over the past 20-odd years," he explained. "Everything happened so quickly: I went from doing nothing to driving for all these manufacturers."
Westbrook picked out his four seasons racing for Chip Ganassi Racing in IMSA in 2016-19 with the Ford GT in the GT Le Mans class as one of the best periods of his career.
"That was a special time for me," said Westbrook, whose regular driving partner over the four years was Ryan Briscoe.
"We had a good group of people and scored a lot of wins, but unfortunately not the championship. We were second twice and it always went down to the wire - that's one regret I will always have.
"When I look back I think I should have won more, more championships. There were big wins in IMSA, like Daytona and Sebring, but never a championship - that will always rankle."
He singled out his second-place overall finish in the 2015 IMSA points alongside Michael Valiante with the Spirit of Daytona team when he was on the books of Chevrolet as another regret.
"We were a small operation racing against big teams like Action Express Racing and Wayne Taylor Racing and we came within three points of the championship," he said.
Westbrook also picked the first of his two Le Mans overall podiums, notched up with Glickenhaus Racing, as another highlight.
"Jim [Glickenhaus, the marque founder] put his money where his mouth was and we achieved everything we could," said Westbrook. "To stand on the Le Mans podium with him was really special."
The three Le Mans podiums in class came in 2010 in GT2 with the Scuderia Italia Porsche team and in 2016 and 2020 respectively with Ford and Aston Martin in GTE Pro.
He was also a race winner in the FIA GT1 World Championship with the JRM Nissan team in 2010 and in class in FIA GTs with the Prospeed Porsche squad in 2008 and '09.
Westbrook was a frontrunner in the Formula Opel Lotus Euroseries one-make single-seater championship in 1994-95, but a proposed F3 drive with the KMS-run Benetton Junior Team in Germany fell through for 1996.
He then stopped racing after a handful F3 races in Germany and Austria that year and didn't resume until coming back for a short self-funded partial programme in the Supercup in 2002.