Lewis Hamilton forged a large chunk of his success with the Mercedes Formula 1 team, having opted to make the switch from McLaren for the 2013 season.
Hamilton had been associated with McLaren for some time, and the story of the young Briton approaching Ron Dennis during his karting years is well documented. In 1998, Ron Dennis offered Hamilton a role in McLaren’s driver development programme.
As he rose through the single-seater ranks, Hamilton finished third in the Formula Renault UK championship in 2002 before winning the title the following year.
However, in 2004, a rift appeared between the Hamilton family and McLaren. While Lewis’ father Anthony wanted to push a 2005 GP2 drive, McLaren wanted Hamilton to stay in the Formula 3 Euro Series for another season after ending his rookie season in fifth.
The fallout was so severe that Martin Whitmarsh, who was part of the McLaren set-up prior to his CEO role, ripped up Hamilton’s contract.
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After the row, Hamilton’s camp approached Williams to talk about a deal.
However, negotiations fell through as BMW, who was in partnership with Williams at the time, was unwilling to fund Hamilton’s junior career.
“They rang up and said 'Can we come and see you?’," said Williams co-founder Patrick Head several years later. "And they came in and said 'Ron Dennis has dropped us'.
"We were with BMW at the time and I think Frank [Williams] rang Mario Theissen [BMW Motorsport Director] and said 'Look, this guy looks as if he could be pretty good and he has come to us saying can we help him?'
"And I think Mario said they weren't prepared to provide any support and we weren't in a position financially where we could finance his racing.
"So much to Frank's annoyance, he could have had Lewis in a Williams."
A number of weeks later, Hamilton returned to McLaren and raced another season at F3 level before progressing to the GP2 Series in 2006 - his last year in single-seater racing before his switch to F1.
How would Hamilton at Williams played out?
It’s almost impossible to say how Hamilton’s F1 career could’ve played out had he joined F1 with Williams instead of McLaren.
The 39-year-old has spoken about his admiration for the team before, stating in 2020 after the Williams family stepped away from running the team: “I remember dreaming of driving the car that [Nigel] Mansell had, or one of DC's [David Coulthard's] cars or something.
“But it never turned into a real option for me. And that's when I moved obviously to Mercedes.”
In 2007, Hamilton's rookie year, Williams had Nico Rosberg locked down on a multi-year contract. Rosberg and Hamilton were good friends at the time, having known each other from their karting days.
The two would go on to endure a famous rivalry at Mercedes when the Brackley-based squad was launched into a dominant position at the start of the turbo-hybrid era.
Hamilton would have been a natural fit inside the team following the departure of Mark Webber and Williams would have likely tried hard to keep Hamilton locked down long-term, given his British ties and raw racing ability.
In the years that followed however, Williams was largely uncompetitive as it finished now higher than sixth from 2008 to 2013.
Being so early in his career, Hamilton likely would have sought a new challenge in more competitive machinery - perhaps even an alternate career path would have led the now seven-time World Champion to a drive at Mercedes.