Horner reveals Hamilton nearly made bombshell Red Bull switch

Writing in his memoir Drive, the former Red Bull team principal explained that the seven-time world champion was actively exploring an exit from McLaren and had identified Red Bull as his preferred destination.

However, the prospect of placing him alongside Sebastian Vettel, who was firmly established as Red Bull's leading driver at the time, raised concerns, while the financial demands involved in completing the transfer also proved difficult to justify.

Hamilton's future became a major talking point during the 2012 season as McLaren struggled with reliability problems. Horner, who regularly encountered the Briton around the paddock, began to suspect that the relationship between the driver and his team was deteriorating.

"Lewis Hamilton seemed to be losing heart at McLaren," Horner wrote. "From the outside, his relationship with Jenson Button looked strained, and his head was dropping after a series of mechanical failures throughout 2012."

The Red Bull boss also noticed a difference in Hamilton's behaviour during their occasional conversations, despite the rivalry between their respective teams.

Horner's suspicions intensified after he noticed an unexpected call from Hamilton's father, Anthony. The contact made him wonder whether the McLaren driver was beginning to reconsider his previous stance towards Red Bull: "While checking my phone for missed calls and messages one day, I noticed his father's number on the screen and wondered whether Lewis was experiencing a change of opinion regarding Red Bull."

Those suspicions were subsequently confirmed when Hamilton agreed to meet Horner and Newey privately at the latter's home near Ascot: "When a secret meeting was then called, with Lewis, at Adrian's house near Ascot, my gut instinct was confirmed. He was looking to leave McLaren, and we were his preferred destination."

According to Horner, Hamilton immediately made his intentions clear, asking what would be required to become a Red Bull driver. Newey was particularly enthusiastic about the possibility, with the team potentially able to field two world champions in the same line-up.

Despite the interest generated by Hamilton's approach, the possibility of signing him was met with reservations from Helmut Marko. The Austrian had been instrumental in Vettel's rise through the Red Bull system and was concerned about how the arrival of another established world champion might affect his protégé.

"Certainly, Helmut looked unimpressed when he heard the news," Horner recalled. "Lewis's arrival would likely impact Sebastian, his protégé, and he was clearly feeling apprehensive."

Horner still explored the possibility of reaching an agreement, opening discussions with Hamilton's representative Simon Fuller. However, the negotiations quickly revealed the scale of the financial commitment Red Bull would have to make.

Fuller's expectations left Horner questioning whether the potential benefits of signing Hamilton would outweigh the costs involved: "I laughed, having grown familiar with the sports-agent vernacular. Simon was going to make a lot of money. And Red Bull would have to spend a fortune."

Although Hamilton's commercial appeal was considerable, Horner ultimately chose not to push ahead with the proposed agreement: "Despite the undeniable marketing upside, I didn't pursue the idea with any real forcefulness. But the Lewis deal was going to appeal to someone. And I had a good idea of who that someone might be."

That team turned out to be Mercedes, which secured Hamilton's signature for the 2013 season. The Briton subsequently won six world championships with the German manufacturer, adding to the title he had already claimed with McLaren in 2008.