Inside Max Verstappen and Lando Norris' bromance gone bad: They've been friends since childhood - and fly to races together - but has their relationship nose-dived following their Austrian GP collision?

Max Verstappen versus Lando Norris has threatened to be the rivalry that would headline Formula One for the next decade.

After three world championships - two pretty much uncontested - in a row, the dominant Dutchman finally appears to have a challenger at the front of the grid in the form of an old rival. And Norris just happens to be one of his friends.

Verstappen and Norris have known each other for a lot of their lives. You may have seen the various photos from 2013 from their karting days.

Just two years separate the pair - Verstappen is 26 and Norris 24 -  who grew up together. They were rivals but friends, though the latter may now be slipping following drama at the Austrian Grand Prix on Sunday.

Their rivalry came to a head in very public fashion, with both left angry after a collision cost them both the chance of victory. Their races were ruined but their friendship was tested, too.

Both are refusing to back down. Other drivers are chipping in. History is being brought up. But who was at fault?

The result of the race would suggest Verstappen. He was handed a 10-second time penalty for his role in the collision - Norris five - which occurred when Brit tried to go around the outside of the Red Bull driver seven laps from the end.

It's possible they touched twice in the collision. Verstappen braked late, 'trying to run him off the road', according to Martin Brundle on Sky Sports. Both men ended up going off, allowing George Russellto claim just his second Grand Prix victory.

What would have likely been the two stars enjoying themselves, joking side-by-side in the cooling room again as they prepared to step back onto steps one and two on the podium, became the potential end of a friendship. Norris demanded an apology, telling Sky Sports: 'I looked forward to a strong, fair battle but I wouldn't say that was what it was in the end. I got taken out of the race.'

He continued: 'There's rules and if the rules aren't followed there's nothing I can do about that. What I was doing today was easily enough for the win.

'I'm doing a good job and happy with my efforts. I can't do anything more than what I've done. Got let down today.'

Pushed on if the friendship would be damaged, he said: 'I don't know. It depends what he says. If he says he did nothing wrong then I'll lose a lot of respect for that. If he admits to being a bit stupid and running into me and being reckless, then I'll have a small amount of respect for it.'

But Verstappen, in true Verstappen fashion, wasn't having it. 'I always move my wheel before I brake and then of course you brake in a straight line trajectory,' he said. 'It's always easy to say I was moving under braking but I think the guy in the car knows best. Everyone can have their own opinion but I'm the one driving. From the outside, it's easy to judge and comment.

'I felt sometimes like he divebombs and he's so late on the brakes. I think it's also just the shape of the corner which provides these kinds of issues sometimes.

'I need to look back at what and how we touched. Of course we'll talk about it. It's unfortunate it happened.'

So that's all we know from the drivers so far. Norris will want to be happier at his home Grand Prix this weekend, but time will tell if the friendship is mended by then.

Last year, Verstappen called Norris his 'best friend on the grid'. 'I get on really well with Lando because he is just himself and normal', he said. 'He is my best friend on the grid. He loves what he is doing. I could see clearly from years ago in go-karting that he was very quick — though we never raced against each other. Everything just came to him really naturally as a driver.'

Norris later added: 'I'll agree with that, let me start with that, I think me and Max are very good friends, I guess we've grown up, not exactly together as we didn't fully race until Formula One, but we've grown up in a similar generation and similar time.

'Certain mentalities are similar, in terms of we're here because we love it, we want to enjoy every minute in the paddock driving cars that we love to drive but as soon as you put the helmet on you forget about everything else.

'We have the correct amount of respect away from the track where you can get on and be mates and it's not like we see each other every day or text each other but we get along and sometimes bump into each other and go for dinner or go for a crepe or whatever it is.'

They also often share flights to travel to races, while Verstappen and Norris were pictured with Dutch DJ Martin Garrix at a party in Miami around the Grand Prix last year and following his set at the Tomorrowland festival.

Norris also once said he would learn Dutch to speak his mate's language. He may now might as well save his time. 

There are those in F1 who already believe the pair can no longer be friends. 'Can two championship rivals ever be friends? No way,' said Sky Sports F1's Ted Kravitz. 

'They can’t be sharing all of this stuff and having great times at Ibiza and Martin Garrix, et cetera, et cetera. They can’t be friends. It’s not possible. So is today the first day that we saw it?'

At least others saw the funny side. 'Cool fight though, that was a very cool fight,' Russell said in the cool room post-race. 'Well, you did just win a race because of it,' Oscar Piastri, Norris' team-mate, responded.

It would be brave to bet against both men being at the front of the grid again this weekend. The most-interesting aspect of their interactions, however, may be off the track.

It takes determination, confidence, and a will to win to reach the top level of elite sport. And those attributes, more often than not, rank above friendship.