Christian Horner has been sacked by Red Bull after 20 years as team principal, the team confirmed Wednesday.
Horner has been in charge of F1's Red Bull team since 2005 and oversaw its dominant runs at the start of the 2010s and the current decade.
Sources within Red Bull have told ESPN that the atmosphere within the team has grown increasingly tense, a situation magnified by struggles on track this year and the growing uncertainty about star driver Max Verstappen's future.
Sources have also told ESPN a series of meetings took place over the past two weekends -- the team's home race, the Austrian Grand Prix, and the British Grand Prix.
At least one of them involved Verstappen and Oliver Mintzlaff, a senior figure on the company's corporate side who has long pushed for a change to the leadership of Red Bull's racing outfit.
Last month, Horner denied reports he had been sounded out by Ferrari chairman John Elkann about potentially replacing the under-fire Fred Vasseur.
Yet, Horner's role always seemed safe while he retained the support of Red Bull majority shareholder Chalerm Yoovidhya, who co-founded the company with the late Dietrich Mateschitz.
That situation appears to have changed. Sources told ESPN no decision to remove Horner could be made without Yoovidhya's approval.
Wednesday's news comes a year after Horner kept his role following an internal sexual misconduct investigation stemming from allegations from a former Red Bull Racing employee.
That only deepened the political rifts that followed Mateschitz's death in 2022.
Horner had a much-publicized falling-out with Jos Verstappen, father of Max. The Verstappens are closely aligned with Red Bull adviser Helmut Marko.
The last year also saw legendary technical director Adrian Newey leave for Aston Martin.
Former Racing Bulls team principal Laurent Mekies has been promoted to CEO of Red Bull Racing.
Under Horner, Red Bull won eight drivers' championships and six constructors' championships.
The team has claimed all of its 124 grand prix victories under his leadership.
Frustrations around the team have been clear to see this season, with Verstappen repeatedly vocal about his issues with the car.
Verstappen's future with the team has also been thrown into doubt, with Mercedes monitoring the status of exit clauses in his contract related to performance.
"We would like to thank Christian Horner for his exceptional work over the last 20 years," Mintzlaff said in a statement.
"With his tireless commitment, experience, expertise and innovative thinking, he has been instrumental in establishing Red Bull Racing as one of the most successful and attractive teams in Formula 1. Thank you for everything, Christian, and you will forever remain an important part of our team history."
Red Bull has confirmed Alan Permane has replaced Mekies as team prinicpal of the junior team, having previously been Racing Bulls director.