Belgian Grand Prix winner George Russell faces disqualification as his Mercedes Formula 1 car was found to be underweight after having its fuel drained in post-race checks.
The Briton clinched a third F1 victory after switching strategies to a one-stopper, and held off a rapidly-chasing Lewis Hamilton for the lead until the end.
However, post-race checks by the FIA have shown that the car still had fuel in it when drained to the 798kg weight limit and, after the rest was taken out of the car, the weight dropped to 796.5kg.
The FIA technical delegates' report reads: "After the Race, car number 63 was weighed and its weight was 798.0kg, which is the minimum weight required by TR Article 4.1.
"After this, fuel was drained out of the car and 2.8 litres of fuel were removed. The car was not fully drained according to the draining procedure submitted by the team in their legality documents as TR Article 6.5.2 is fulfilled.
"The car was weighed again on the FIA inside and outside scales and the weight was 796.5kg. The calibration of the outside and inside scales was confirmed and witnessed by the competitor.
"As this is 1.5 kg below the minimum weight requested in TR Article 4.1, which also has to be respected at all times during the Competition, I am referring this matter to the Stewards for their consideration."
This is expected to result in Russell's victory being thrown out, in the likely event that Mercedes cannot explain the 1.5kg discrepancy between his car and the minimum weight.
The FIA's sporting regulations state that, in Article 35.3: "The relevant car may be disqualified should its weight be less than that specified in Article 4.1 of the Technical Regulations when weighed in accordance with Articles 35.1 or 35.2, save where the deficiency in weight results from the accidental loss of a component of the car."
Hamilton would thus be granted with the win over Oscar Piastri, while Charles Leclerc would be moved up to third.
This would not be the first disqualification that Mercedes' historical lineage has faced for being below the weight cap, but at this stage the team hasn't be found to have deliberately misled F1 officials.
BAR had its results from the San Marino Grand Prix thrown out as both Jenson Button and Takuma Sato's cars were found to be underweight when fully drained of fuel, as a secret secondary fuel tank was used as ballast.
Tyrrell also had its 1984 results expunged as it was discovered that the team had topped up its water injection system throughout the races with a mixture of water and lead shot, which raised the underweight 012 above the 540kg minimum weight limit.
