This move came in response to Mercedes' "public courting" of Max Verstappen, as detailed in Horner's new autobiography, Drive.

According to ESPN, Horner explained that he decided to "fight fire with fire" after growing increasingly frustrated with Toto Wolff's attempts to lure Verstappen away from Red Bull.

The approach to Russell's management happened during the 2025 British Grand Prix weekend at Silverstone, which was Horner's last race in charge before his dismissal a few days later.

At the same time, Horner held private discussions with Verstappen about his future and met with Carlos Sainz to talk about the possibility of him driving for Red Bull.

Mercedes had been showing interest in Verstappen due to uncertainty around Red Bull's competitiveness and speculation that a clause in his contract could allow him to leave during the summer break if he wasn't in the top three in the drivers' championship.

"This situation was being aggravated by Toto, who was still doing everything he could to lure Max to Mercedes," Horner wrote.

"At one point, Flavio Briatore approached me to say that Toto was convinced that Max would be a Mercedes driver in 2026.

"By that stage, I felt sorrier for George Russell.

"As a Mercedes driver, he must have been bemused at the situation."

Horner said he eventually decided to speak directly to Verstappen ahead of the British Grand Prix.

Horner wrote that Max Verstappen told him: "I want to win.

"But I don't want to have to leave to do it."

He added that Verstappen said: "Mercedes are making noise.

"And of course the media writes what suits them.

"But Christian: I started my career at Red Bull.

"I want to finish it here, too."

Horner said he told Verstappen he could not guarantee Red Bull would be competitive under the new engine regulations coming in 2026, but that he would have plenty of options for 2027 if the team struggled.

Having clarified Verstappen's position, Horner turned his attention to Red Bull's second seat, with Yuki Tsunoda struggling to deliver consistent results.

Horner wrote: "On the Thursday night, ahead of practice, Carlos Sainz Jr visited the house to discuss a potential 2026 move to Red Bull.

"He was an established Grand Prix driver, a team player, and I knew he'd work his backside off for the team."

But Horner was also considering another option, becoming increasingly frustrated with Wolff's public pursuit of Verstappen.

Horner wrote: "Having grown tired of Toto's challenging approach, I decided to fight fire with fire and approached George Russell's management for a meeting.

"George was coming to the end of his contract, and if it was OK for Toto to constantly talk about my drivers, then I saw no harm in talking to his about a potential move to Red Bull."

Horner's tenure as Red Bull team principal and CEO ended shortly after these incidents, concluding a career that began with the team's F1 debut in 2005.