Fernando Alonso and Lewis Hamilton's spectacular Hungarian GP fall-out in 2007 set the wheels in motion for McLaren to lose two titles and to be excluded from the Constructors' Championship, while it also paved the way for their two-time world champion to leave.
It was a tempestuous and ultimately destructive year-long partnership, and it all came to a head in a single qualifying session.
Here, we remember the drama and furore 10 years on…
Setting the scene
From the moment Fernando Alonso replaced Michael Schumacher as F1's fastest man, he was a driver Ron Dennis simply had to have. The Spaniard's journey with McLaren may not have officially started until 2007, but he had agreed a deal two years earlier following his first title triumph at Renault.
One thing Alonso may have expected upon beginning life as a McLaren driver was No 1 status and superiority, and that looked probable following Juan Pablo Montoya and Kimi Raikkonen's unexpected Woking departures in 2006. Dennis needed to find a competent second driver to complement his star man - and he eventually opted for a gifted youngster he had backed ever since first meeting him at the age of nine.
What neither Dennis nor Alonso foresaw was just how quick Lewis Hamilton would be.
Hamilton was highly rated as a driver who had just comprehensively sealed back-to-back championships in Formula Three and GP2, and was keen to lay down his marker immediately. Alonso qualified second for the Australian GP, with Hamilton fourth, and both finished on the podium, but the rookie's statement of intent - passing his team-mate at the start of the race - was duly noted.
Hamilton knew he was quick and even claimed team orders cost him his first F1 victory in Monaco, a public remark which clearly goaded Alonso. The two-time world champion had already admitted his new team-mate was firmly in the title race, but his emergence also seemed to be affecting Alonso and his relationship with senior McLaren personnel.
"I have a British team-mate in a British team, and he's doing a great job and we know that all the support and help is going to him," Alonso was quoted as saying in the Spanish press.
Hamilton was a consistent threat and podium-finisher from the off but his maiden F1 race win in Canada, immediately followed by victory at Indianapolis as a disgruntled Alonso criticised his team, meant a sensational debut title was now a distinct possibility. Heading to the Hungarian GP, round 11 of the 17-race championship, Hamilton led Alonso by two points with Ferrari's Felipe Massa and Raikkonen more than a race win adrift.
Not only that but Hamilton was also 6-4 up on his McLaren colleague in qualifying when outside factors rarely come in to play - meaning the pressure was well and truly piling on Alonso.
And off the track?
All the while, a scandal which is now known as 'Spygate' was rumbling on in Woking. McLaren's chief designer Mike Coughlan had been sent 780-pages worth of Ferrari design documentation by their former chief mechanic Nigel Stepney, and while both men were sacked by their teams, an FIA investigation could find no evidence the information had been seen by anyone else.
A Budapest bust-up
Qualifying at the Hungarian GP brings a reminder to 'fuel-burning' laps cars did on a Saturday back then - and McLaren had a system whereby one driver would have the advantage of an extra lap's worth of fuel during qualifying at certain circuits, such as the Hungaroring.
On August 4, 2007, it was Alonso's turn to lead the way in qualifying.
But when Hamilton took to the front and refused to let his team-mate pass - claiming that Raikkonen would then get through if he had done so - Alonso fumed, and duly retaliated when it came to McLaren's final Q3 pitstops.
Hamilton was leading at this stage of qualifying but the final laps were sure to be quicker, and McLaren chose to stack both cars in the pits, holding Alonso for around 20 seconds with Hamilton stuck behind in an attempt to give their drivers as much track space as possible. The lollipop was lifted for Alonso with one minute and 48 seconds left in the session, ample time for both drivers to complete their low-fuel laps.
Two seconds later and Alonso was still there… five seconds… seven, eight, nine... and finally, after yet more theatrical hand gestures, the Spaniard was out of the pits. But the damage was already done - Hamilton had been held up by 10 seconds, and didn't have enough time for a final flying lap. Alonso, meanwhile, had snatched pole by a mere 0.107seconds.
Not long after a predictably tense post-qualifying press conference, in which an enraged Hamilton was asked as to how long he missed out on setting a final quick lap - "about the same amount of time I was held up in the pit stop," his no-nonsense reply - the race stewards launched their investigation into the incident and asked McLaren to submit all their radio transmissions.
Dennis, despite remonstrating with Alonso's physiotherapist Fabrizio Borra immediately after the fiasco, initially shielded the Spaniard and lay the blame on the team's pit strategy and Hamilton. There were even rumours, since denied by both parties, of an expletive-laden dispute over team radio between the pair.
Alonso was staunch in his defence, too. He claimed McLaren were holding him back in the pits, something they had done earlier in the session. The 10-second delay after the lollipop was raised? That was down to a discussion with race engineer Mark Slade about why used tyres had been fitted, according to Fernando. But again, this raised more questions than answers. Why couldn't that chat have taken place in the previous team-enforced 20-second wait?
The officials deliberated long and hard, so much so that their verdict didn't appear until around midnight local time, some eight hours after Dennis was first summoned to the stewards.
That wait would have been particularly uncomfortable for Alonso, who can't have been too surprised when he learned his fate. The double world champion was struck with a five-place grid penalty for "unnecessarily impeding another driver", handing Hamilton top spot and an undeniable advantage in a crucial grand prix.
But the punishment was perhaps even more severe for McLaren, who were informed they would not be receiving any constructors' points in Hungary. Sensationally, one of the sport's most successful teams were essentially accused of lying.
"The explanation given by the team as to why they kept Alonso stationary for 20 seconds after completion of his tyre change and therefore delayed Hamilton's own pit stop is not accepted," the FIA's judgement added. "The actions of the team in the final minutes of qualifying are considered prejudicial to the interests of the competition."
By the following morning, Alonso had been quickly demonised and savaged by the British press for blocking their new sporting hero. But more controversial was the impression McLaren had turned their back on the Spaniard.
"The process of managing two such exceptional talents in Fernando and Lewis is made more challenging by having a race winning car," a pre-race team statement read. "Every effort was made [in qualifying] by the team to maintain our policy of equality; however in the heat of the battle there are occasions when the competitive nature of drivers sees them deviate from the agreed procedures."
Deviate, Alonso had, and the pre-race drama and chaos was not done there. During an argument with Dennis on that same Sunday morning, the then 26-year-old reputedly told his boss he had emails relating to the Ferrari leak. Was this blackmail in an attempt to secure No 1 status, or a mistake in the heat of the moment?
Either way, despite Alonso's apology, Dennis reported his driver's claims to FIA president Max Mosley - thus unintentionally opening up his team to more investigations…
What happened next?
Hamilton led every lap of the race to seal a sublime Hungarian GP victory, with Alonso only able to salvage fourth place. But that's barely worth noting compared to the explosive fall-out and rapid divorce. This was the beginning of the end for McLaren and Alonso, with Dennis' relationship with a driver he had strived so hard to get quickly deteriorating.
Starting with 'Spygate' and, after re-opening its investigation, the FIA decided that McLaren did, after all, disseminate Ferrari's technical data and fined them $100m, while they were also thrown out of the Constructors' Championship.
"The relationship between Fernando and myself is extremely cold," said Dennis during the FIA's hearing. "That is an understatement."
McLaren would not be the top constructors but Dennis was still eager to have a drivers' champion in 2007 and was seemingly adamant it would be Hamilton, who had led in the standings throughout the summer. At the penultimate race of the season in China, with Hamilton 12 points ahead of his team-mate and 17 clear of Raikkonen, Dennis even admitted that McLaren were "racing against Alonso". The plan didn't work - Hamilton found his car dribbling into the gravel at the pit-lane entry for his first retirement of the year, while Alonso finished second behind Raikkonen.
The Ferrari driver would go on to take victory at Interlagos and a first F1 title as Hamilton, needing only to finish fifth, could only manage seventh after a first lap battle with Alonso and gearbox troubles. Alonso, who had earlier asked an FIA steward to inspect his car in the garage to ensure equal treatment at McLaren, was third and like Hamilton, missed out on the championship by a single point.
Alonso was out the door a month later, with McLaren effectively making the sport's most illustrious driver a free agent after severing their three-year contract. Renault were happy to take their former protégé back.
10 years on…
A lot can happen in a decade in any sport, particularly in the ever-changing circus that is Formula 1. For one, Dennis has left his McLaren dynasty and the sport's eight-time champions are currently bottom of the constructors' standings. And that's not even mentioning the drivers.
Alonso has since moved to Ferrari and returned to McLaren, signing another three-year contract in 2014 as both he and Dennis insisted they had patched up their differences. Alonso joined a team in transition, with a new Honda engine partnership, a year after Hamilton had jumped ship for Mercedes. Right now it is clear to see which driver has made wiser career choices.
Hamilton is a three-time world champion and has a good chance of clinching a fourth this season, while Alonso, despite widespread recognition he is still driving at his very best, has been waiting 11 years to add to his two titles.
Wolff: Lewis building a legacy
Another championship is still on his agenda and Alonso, out of contract at the end of the season, says he will not sign an extension with McLaren unless they prove they are capable of winning in 2018. He has been sounding out Mercedes in a bid to partner his former team-mate once again but, as yet, neither the Silver Arrows nor Hamilton have been too welcoming of the links.
Alonso's decision on his future is due after the summer break, and the closest these two could get to each other in the second half of the campaign may just be in the pits…
What they've said since
Fernando Alonso
2009 - "We had a good competition which helped each other to find our limits. I can say that maybe I am missing that competition in a way because, as I said, it was quite fun to really push and find new limits from ourselves."
2016 - "If I was team-mate of Lewis one day I think it would be very different, because we have learned and we are very different people. We no longer have that ... let's say that stress of winning on the side because I think we respect each other a lot."
Lewis Hamilton
2010 - "I definitely didn't blame myself for the year that I missed out. My first season in Formula 1, alongside a world champion - a double world champion - and I blew him away. I beat him."
2016 - "Bring Fernando, bring whoever you really want. I drove against Fernando in my first year and I beat him, so that's not a worry for me. I'm happy to drive against any of them, but in terms of what's best for the team, probably not the best idea."
2017 - "My relationship with Fernando was toxic and it intoxicated the whole team. So yes it was personal."
Ron Dennis
2010 - "It was very simple - Alonso didn't expect Hamilton to be that competitive in his first year. He told me at the beginning that it was my decision to sign a rookie like Hamilton, but that it could cost me the Constructors' Championship. Fernando was calculating everything, but not that Lewis would challenge him. That affected him massively."
2015 - "If you go back to that period, you look at the chemistry and we had Lewis, a young guy, understandably perceived by many people as the chosen one but also someone who had immaturity.
"If you go on the 'who struck the first blow' route, actually I would say that Lewis had his role to play in starting this process which escalated."
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