Red Bull accuse McLaren of illegally injecting tyres with water as bitter world championship fight spills off the track at the Brazilian Grand Prix

Red Bull have accused McLaren of illegally injecting water into their tyres to cool them on the eve of the Brazilian Grand Prix.

The constructor believes the water — or another unspecified substance — has been inserted via a valve. The coolant would then help guard against degradation, and so deliver better race pace.

Suspicions were raised in Singapore when, as the accusation goes, a jet of water flew off the tyre rims post-race.

Red Bull have alerted the FIA of their suspicions. The governing body will be extra vigilant in monitoring this from now on.

McLaren dismissed the accusations. And spokesman for tyre suppliers Pirelli said that if they found anything suspicious, they would have informed the FIA. Pirelli collects all tyres and analyses them after each race.

McLaren have dismissed the accusations, while a Pirelli spokesman has insisted they would have informed the FIA if they found anything suspicious

Using water or another substance to cool tyres shortly before they are fitted to their cards in the race could help limit thermal degradation and help drivers deliver better pace, especially in the closing stages of the Grand Prix. 

The FIA issued a technical directive banning the practice, which a several teams including Red Bull have used in the past, a number of years ago. They now suspect their rivals if doing the same and believe it might explain their performance advantage. 

The accusation is a product of an increasingly fraught fight for the drivers’ title between Lando Norris and Max Verstappen which will be decided here and in three concluding races in Las Vegas, Qatar and Abu Dhabi.

McLaren’s ‘mini-DRS’ was the most recent development that came under scrutiny from their rivals. Ahead of the Singapore Grand Prix, the constructor announced their were ‘proactively’ tweaking the design after ‘conversations with the FIA’.

The reigning world champion saw his lead at the top of the driver’s standings cut to 44 points on Saturday after Norris was gifted a win in the sprint race by team-mate Oscar Piastri. 

However, McLaren hold a commanding lead over Red Bull in the constructor’s standings. Indeed, the Milton Keynes-based outfit is not currently their closest challenger. 

Ferrari trail McLaren by only 34 points going into the final four races of the season, while the gap to Red Bull stands at 63 points.