Three-time champion Gordon Shedden has parted ways with Team Dynamics and will not contest this year's British Touring Car Championship.
The 38-year-old Scot has spent all but one of his 12 seasons in the category's top flight full-time with the West Midlands team, which runs the factory-backed Hondas in the series.
Shedden has won 48 races over that period.
Sources suggest Shedden could be about to embark on a season of international racing.
Shedden was drafted in to the WRT team for the final round of the TCR International Series in 2017 in place of Rob Huff and was asked to assist his title-chasing team-mate Jean-Karl Vernay in the Dubai races.
Vernay went on to win the title while Shedden, who had secured pole, finished second in the weekend's opening race.
Team Dynamics has yet to reveal who will partner Matt Neal in the new-shaped Honda Civic Type Rs in the BTCC this term.
A team statement said it would announce Shedden's replacement "in due course".
"[This] is really difficult and emotional for me," said Shedden, who clinched the BTCC silverware in 2012, '15 and '16.
"I will not be racing with Honda and Team Dynamics: they have been part of my life for the last 11 years and I have been made to feel a part of the family.
"Steve and Matt Neal gave me a chance [to join the team] in 2006 and we haven't looked back since.
"From a Ford Fiesta racer to a triple British Touring Car champion, I could not have dreamed of the success we have achieved together.
"That success, along with Matt's three championships, is a testament to the hard work, determination and passion that is intrinsic in the team."
Shedden's on-track team-mate and Dynamics team owner Matt Neal said: "Gordon is a part of our family and success story.
"He's got a new and exciting opportunity and we would never hold him back from that."
Shedden's BTCC career in numbers
Fastest laps 51