Why Mercedes wants a review of the Lewis Hamilton-Max Verstappen incident

Following the Sao Paulo Grand Prix, Mercedes team principal Toto Wolff likened his team's race weekend to being punched multiple times in the face. He said he was "angry" that decisions by the FIA stewards had consistently swung against his team and went on to say that, from his perspective, the time for "diplomacy has ended".

Given the strength of his words, it was perhaps no surprise that Mercedes wrote to the FIA on Tuesday saying it had requested a review of one of the more controversial incidents in the race. Wolff had described the stewards' decision not to investigate the near collision between Max Verstappen and Lewis Hamilton on lap 48 as "the tip of the iceberg" and "laughable".

But to understand how we got here, you need to rewind to Friday afternoon in Interlagos and the first decision that went against Mercedes.

In the qualifying session for Saturday's sprint race, Hamilton had took pole position by 0.4s only to be disqualified from the session when the drag reduction system (DRS) on his car failed a routine test. The flap in the rear wing that opens to reduce drag and increase top speed, opened 0.2 mm further than the 85mm permitted under the regulations. It was only on one side (the right when viewed from the rear) and only when it had pressure forced upon it, but in the black and white world of the technical regulations it was a fail.

Mercedes believed the failure was due to damage to the wing, although the mechanics were not allowed to inspect the components until after the race weekend or attempt to fix the damage to show that the wing was intended to be legal. In fact, the stewards never doubted the legality of Mercedes' intended design and agreed the most likely reason for the wider opening was down to damage. But a failed test is a failed test regardless of how it comes around, and by the time it is put in front of the stewards they have little choice but to apply the rules and disqualify the car.

Things got murkier on Friday evening when it emerged that the last person to touch the wing before it failed the test was Hamilton's title rival Max Verstappen. The Red Bull driver said he was looking for proof of a different violation of the rules to explain Mercedes' impressive straight-line speed at Interlagos, but his involvement meant the investigation had to be adjourned until Saturday morning so that video footage could be obtained and Verstappen could be summoned to the stewards' room. Verstappen was fined €50,000 for his actions as they breached parc ferme regulations, but both the stewards and Mercedes agreed the failed DRS test was completely unrelated. Soon after the fine was issued to Verstappen, Hamilton was disqualified from the results of qualifying due to the DRS test.

Why did Mercedes request a review?

In Saturday's sprint race, Hamilton fought his way back from last on the grid to fifth in 24 laps -- a hugely impressive performance that would have left him fifth on the grid for Sunday's grand prix had it not been for a five-place engine penalty, which dropped him to tenth. There was no argument over the engine penalty from Mercedes, which the team decided to take after balancing it against the advantage of running a fresh a motor over the final four races.

Starting tenth, Hamilton fought his way back through the field to second place in the first half of the race before chasing down Verstappen for the lead. At Turn 4 on lap 48 he got his first clear opportunity to overtake his title rival, but Verstappen put up an aggressive defence as Hamilton went to the outside of the Red Bull, which saw both cars sail wide and into the run-off zone.

The incident was noted by race control but not investigated by the stewards on the grounds of F1's rarely applied "let them race" principle. The "let them race" idea is several seasons old but it remains a woolly concept that is not written down in the rules and is often ignored in favour of the actual rules in both the Sporting Regulations and the International Sporting Code. For example, "forcing another driver off the track" is a breach of Appendix L, Chapter IV Article 2 of the FIA International Sporting Code, which has been applied a number of times this year, notably at the Austrian Grand Prix when Lando Norris ran Sergio Perez out of road at Turn 4.

Despite the drama on lap 48, Hamilton passed Verstappen successfully a handful of laps later to secure the lead. He went on to win the race, take 25 points and close the gap to Verstappen in the drivers' standings to 14 points. But the drama didn't end there.

After the chequered flag there were rumours that Red Bull might protest Mercedes' victory based on suspicions about the car's rear wing, but team principal Christian Horner told Sky Sports "we won't be protesting at this race." The phrasing seems to leave the door open to a protest at another round later in the championship, perhaps once Red Bull has gained clarification on certain issues from the FIA. While Mercedes may be confident it could fend off any protest about the legality of its car, the prospect of a protest is still hanging over the final three races as relations between the teams reach an all-time low.

And then, just as Mercedes was about to line up for its team photo and crack open the champagne, its team manager Ron Meadows was called back to the stewards office to explain why Hamilton undid his safety belts on the slowing down lap after the chequered flag. Video footage clearly showed Hamilton with his shoulder belts undone while he waved to the crowd and took hold of a Brazilian flag. There was really no defence for Hamilton's actions, and so a financial penalty was handed to the driver on the basis that he not only put himself at risk but also set a bad example for young drivers in junior categories. All fair enough, but when the stewards first summoned Meadows there was a sense of "what now?" after so many trips to the stewards office over the weekend.

Remarkably the fallout from the Sao Paulo Grand Prix continues to drag on as F1 arrives in Qatar for the next round. When more onboard footage emerged of the lap 48 incident from Verstappen's car on Tuesday, Mercedes requested a right to review the decision not to investigate the Red Bull driver. The front-facing camera angle from Verstappen's car was not available to the stewards at the time of the incident, so it is entirely possible that it could change their opinion on whether it warranted an investigation and whether a penalty should be issued.

The footage itself shows Verstappen was very optimistic in his approach to making the corner, braking later than Hamilton and unable to load the steering with an angle that would get him anywhere near the apex or ensure he stayed on the track. But there are very few people who know what it's like to race a car wheel-to-wheel in those circumstances and so the judgement of whether he did anything untoward will likely come down to the two ex-drivers on the Brazil stewarding panel, Vitantonio Liuzzi and Roberto Moreno.

Liuzzi raced in 80 grands prix between 2005 and 2011, including for Red Bull and its junior team Toro Rosso before he was dropped by its driver programme. Moreno's experience is less recent and he last raced in F1 in 1995. If Mercedes' right to review is accepted, their expert opinions on whether Verstappen made a genuine attempt to take the corner or intended to hold position by running Hamilton off the track will be crucial to the outcome.

It's not clear what that outcome will be or when it will be announced, but as the season enters the final three rounds there's a real danger that one of the greatest championship battles in recent memory is decided behind closed doors in a stewards' office rather than on the track.

Why were Mercedes upset with the other stewards' decisions?

Formula One's technical regulations are complex but the enforcement of them is fairly simple. If you fail one of the post-session scrutineering tests, your car is reported to the stewards and the stewards (assuming the test had been carried out correctly and the car has indeed failed) are obliged to disqualify the competitor from the results.

One other recent example of a similar situation was Kimi Raikkonen's disqualification from qualifying for the 2019 Azerbaijan Grand Prix. Raikkonen's Alfa Romeo failed a front wing deflection test due to damage from the previous race and was excluded from the qualifying results in Baku. In that instance, the team also had to change the specification of wing for the race because it had run out of the original spec, resulting in a pit lane start on the Sunday.

However, there are also stories of cars failing tests due to damage and not being reported to the stewards. These are much harder to verify because they never reached the stage where official documents are circulated. But according to some sources, parts of cars which are easily damaged against kerbs, such as the front of the floor of the car, have failed deflection tests due to damage and the parts have simply been replaced without the need for a penalty.

It's not uncommon for teams to repair cars over a race weekend and a list of substituted parts is published ahead of every race. Teams are also known to strengthen parts by patching over damage to wings or suspension with carbon fibre. However, such running repairs have to be done extremely carefully under parc ferme regulations, so as not to alter the spec of the car or, in patching parts up, change their shape so they no longer conform with the regulations.

We'd be talking incredibly small margins that would serve no performance advantage, but then arguably that was true of Mercedes' DRS issue. It seems Mercedes' constant referencing of Red Bull's rear wing repairs in Mexico, which included patching some surfaces of the wing, were a hint that future repairs of that nature could also be questioned and it wouldn't take much to open a Pandora's box of questions or even protests of rival cars.

If Wolff's message that "the time for diplomacy is over" is meant seriously, then there's a danger the final few races are fought as much in the scrutineering bays and stewards' office as they are on the track.