Sport is full of ‘what if?’ moments – and Formula 1 is no different. What if a driver hadn’t made that split-second decision behind the steering wheel? What if a team boss hadn’t gone against his instincts and signed that driver? As F1 celebrates its 70th anniversary, we’re taking a look back at the moments and decisions that had huge ramifications for the sport and those who participate in it, starting with a sliding doors moment for Lewis Hamilton… What actually happened It began with two laboured press conferences at Suzuka on October 4, 2012. In the first, Michael Schumacher explained, for the second time in his career, why he was retiring. This was the courtesy part of Lewis Hamilton’s shock decision to switch from McLaren to replace him at Mercedes, the Silver Arrows letting Michael have his say first. Then Lewis deadpanned his way through a tortuous press conference in which he studiously avoided making further comment on his forthcoming move. WATCH: Mercedes team mates Lewis Hamilton and Nico Rosberg's epic duel in the desert at Bahrain in 2014

It started with a press conference...

In the paddock, and in print, there was no shortage of sage journalists prepared to commit to their belief that in leaving McLaren for Mercedes, the 2008 world champion was committing career suicide. I was one of them, and boy, has he never let any of us forget that! Rightly so… Of course, with that greatest of all wisdoms – hindsight – we can all look back and laugh. After all, five world championships and another 63 victories are tungsten-solid proof that he was right to yield to Niki Lauda’s blandishments to up sticks and join the team that went on to dominate the era of the turbo-hybrid F1 car. But for an engine failure in Malaysia in 2016, Lewis would have won all six titles. READ MORE: Lewis Hamilton – The ridiculous stats The ‘sliding doors’ moment McLaren wanted to keep Lewis – of that there is no doubt. Chairman Ron Dennis even famously said: “If things pan out the way I expect them to, I'm pretty sure he will be sat in a McLaren next year.” And if you looked at what was happening at McLaren back in 2012, and compared what Mercedes had achieved since 2010, it surely seemed a slam dunk Lewis would stay put. In that three-year period, McLaren won 18 races to Mercedes’ 1. But this wasn’t a situation entirely about current performance or claims of future performance. Lewis wanted the personal freedom he needs to perform at his best, which is part of the reason he left. And the bald statistics say that he was absolutely right to leave McLaren...

Hamilton timed his Mercedes move to near-perfection

The alternative reality But what if Lewis had stayed at McLaren, and not joined the Silver Arrows? What if he had continued to keep the faith, having first approached Ron Dennis when he was a 10-year-old kid doing pretty well in karting? Lauda had clearly decided that Michael was past his best, hence going after Lewis for Mercedes in the first place. And with three titles already won with Red Bull, would Sebastian Vettel have been bold – rash – enough to gamble on walking away from such success to join Mercedes in his hero's stead, given the team’s poor performances up to 2012? READ MORE: Could Ferrari sign Hamilton for 2021? It’s much more likely that the pragmatic Niki would have switched his sights to Fernando Alonso, who by the end of 2012 must have been despairing of Ferrari ever delivering him a world championship. At that stage Fernando had bagged 30 victories – nine more than Lewis had in his pre-Mercedes years – and two titles. Were he to have mirrored what Lewis subsequently achieved with Mercedes – five titles and 63 race victories (and who is to say that he might not have done better still?) – the Spaniard would now have seven titles and 93 victories and be the statistical king of the castle. Now there’s a thought…

Imagine if Alonso had replaced his former arch rival

Mercedes began to turn the tide in 2013, while McLaren fell over the cliff at exactly the same time. That season Nico Rosberg won two races, Lewis one, the Briton starting from pole five times and the German thrice. McLaren, by contrast, had a disastrous year and fell into the slump from which they are only just recovering. They haven’t looked like winning again since 2012. Given that Jenson had scored eight of their 18 victories in the previous years when paired with Lewis, it’s fair to judge that the pair were pretty evenly matched. READ MORE: McLaren confirm switch to Mercedes power in 2021 to go ahead as planned Thus the fact that Jenson’s best score in 2013 was a paltry fourth place in Brazil is a damning indication of just how far the Woking team had fallen, and how much Lewis would also have struggled in a McLaren. Even though he could get more out of a bad car than Jenson could, he would definitely not have been the title fight that year, and it’s not inconceivable that he would have been looking for a move elsewhere by the end of it. But Mercedes’ door would probably have been closed. In our alternative reality Alonso would already have been there, and would they have risked dropping Nico to take Lewis, after the aggro between the Spaniard and the rookie Brit at McLaren in 2007? It’s unlikely. So where else could he have gone? READ MORE: McLaren's Hamilton-Alonso line-up 'strongest there's ever been' says Pedro de la Rosa

Verstappen and Vettel could have been Red Bull team mates – imagine...