Former Red Bull advisor Helmut Marko launched a scathing attack on ex-team principal Christian Horner on Thursday, describing his newly-released memoir as a "collection of untruths".
The 83-year-old Austrian, who was a senior figure in the racing team, said it was "an embarrassment" that the book was being published on October 22, the day of Red Bull founder Dieter Mateschitz’s death in 2022.
Horner, who led Red Bull to eight drivers' titles and six constructors' crowns, was sacked as team principal in July 2025, 17 months after he was accused by a woman colleague of "inappropriate behaviour".
The Englishman was twice cleared over the claims by the Formula One team's parent company, Red Bull GmbH, and his wife, former Spice Girl Geri Halliwell, stood by him.
But there were rumblings of discontent within the team, with several high-profile departures, while form on the track dipped. Horner was formally dismissed in September 2025 with a huge payoff estimated to be as much as £100 million.
Marko said that Horner should have shown more loyalty.
“That’s a collection of untruths,” he told Sky Sports Germany.
“I don’t even want to get into the level of discourse. Especially after the huge settlement he received, one would have expected some loyalty.
“I don’t think he’s even aware that his book is being published on the exact day Dietrich Mateschitz died.”
Marko had previously said that many of Horner's claims made in the book were not true.
'BRUTAL'
Horner, meanwhile, has accused Marko of playing a role in his dismissal soon after his former partner, the mother of his daughter, had died of cancer.
He also claims that Marko did not offer his condolences, a claim refuted strongly by the Austrian.
"The only thing I want to clarify is that I even sent him my condolences in writing, for his ex-partner, who died of cancer,” said Marko, in a further interview with Austrian newspaper Kronen Zeitung. “That’s all that matters to me.”
The pair worked together at Red Bull for more than 20 years.
Horner, 52, told the Autosport Business Exchange conference in New York on Thursday that his departure from Red Bull was "pretty abrupt and quite brutal".
He said he now reflected with pride on his achievements.
“I’m very proud of what we all did there and I feel privileged to have worked with some amazing drivers,” he said.
He also revealed that Red Bull shareholders had recently called him to show their appreciation of his part in the creation of Red Bull’s own power unit, and its maiden victory with Max Verstappen at the Bahrain Grand Prix in Malaysia.
“It was an appreciated gesture,” he said.
“For all the men and women involved, it was an incredible achievement at their 16th attempt to win a Grand Prix, which is very hard at the best of times.
“I was grateful to the shareholders who reached out and to Oliver Mintzlaff (Red Bull’s chief executive) who thanked me as well. It was quite a different call than I had 15 months earlier.”