What Formula 1's safety car restart rules say

With Lewis Hamilton having looked on course to grab his eighth world crown, the race was turned in its head when Williams driver Nicholas Latifi crashed at the exit of the hotel complex on lap 53 of the 58 laps race, triggering a safety car.

The safety car situation resulted in Max Verstappen pitting for soft tyres, while Hamilton stayed out on his well-worn hards.

With a winner-takes-all championship battle underway, it was in Red Bull's interest to get a restart going, and it without the intervention of lapped cars that were on track between Verstappen and Hamilton.

So when Masi issued a notice saying 'Lapped cars will not be allowed to overtake', it appeared that Red Bull's hopes would not be realised as he would be unlikely to clear the lapped cars in time.

However, the situation changed dramatically on the penultimate lap when Masi felt the track was safe enough to let a few backmarkers overtake.

But it was the way this was handled, and the immediate restart, that has upset Mercedes.

Safety Car rules

Lewis Hamilton, Mercedes W12

Photo by: Charles Coates / Motorsport Images

Mercedes' protest is based on two regulations: Article 48.12 and Article 48.8 of the F1 Sporting Regulations.

Article 48.12 deals with the situation of having backmarkers unlap themselves.

Initially, Masi had been within his rights to state that 'Lapped Cars will not be allowed to overtake' - which meant Verstappen would be trapped behind five backmarkers before he could get a run on Hamilton.

However, on the penultimate lap, on the run down to Turn 9, Masi sent a message saying that five cars – Lando Norris, Fernando Alonso, Esteban Ocon, Charles Leclerc and Sebastian Vettel could unlap themselves.

The decision to only allow some lapped cars to unlap themselves is unusual as Article 48.12 suggests that the message 'LAPPED CARS MAY NOW OVERTAKE' should be sent to all competitors.

The regulation is then explicit about when the race can be restarted.

It states: "Unless the clerk of the course considers the presence of the safety car is still necessary, once the last lapped car has passed the leader the safety car will return to the pits at the end of the following lap.

"If the clerk of the course considers track conditions are unsuitable for overtaking the message "OVERTAKING WILL NOT BE PERMITTED" will be sent to all Competitors via the official messaging system "

This clause suggests that with the lapped car message having come out on lap 57, then the restart could only come at the end of the 'following lap'- so lap 58, which was the end of the race.

Article 48.8 relates to there being no overtaking behind the safety car.

During the restart phase, as Hamilton and Verstappen prepared to begin racing again, it appeared from the onboard that the Red Bull had briefly nudged ahead of the Mercedes.

The rule states that "no driver may overtake another car on the track, including the safety car, until he passes the Line (see Article 5.3 – which is the safety car line) for the first time after the safety car has returned to the pits."

Both matters will now be dealt with in the FIA stewards' room on Sunday night, meaning the championship fight ends under a cloud.