Horner, who joined the team in 2005, led Red Bull to eight drivers’ championships and six constructors’ championship titles.
He was dismissed after a controversial 18 months that started when a female employee accused him of sexual harassment, an allegation that was made public in February 2024.
He was twice cleared of the claims, firstly after an internal investigation conducted by a lawyer, then by another lawyer who dismissed the complainant’s appeal.
The Briton left with a £52m payout but he said he felt a “real sense of loss”, and blamed Red Bull managing director Oliver Mintzlaff and Red Bull advisor Marko Helmut for his exit.
“It was all rather sudden. I didn’t really get the chance to say a proper goodbye,” he said.
“I think this was a decision that was made by Oliver Mintzlaff with Helmut advising from the side-line.
“I think ultimately things changed within the business, within the group. The founder died, and after Dietrich [Mateschitz]’s death, I think probably I was deemed to have maybe too much control.”