McLaren’s Fernando Alonso and Jenson Button have each been hit with a 25-place grid penalty for Sunday’s Austrian Grand Prix in Spielberg, even though there are only 20 cars in the race.

On Friday Alonso – who is still looking for his first points of the season – was given a 20-place penalty after McLaren changed his engine. That was increased to 25 places because he changed his gearbox after coming to a halt during Saturday morning’s practice run.

McLaren also learned before Saturday’s qualifying session that Button would be demoted 25 places for having a power unit change ahead of Sunday’s race. He was dropped 15 places in the last race in Canada because of repairs that had to be done following a failure in practice. It is impossible to be demoted further back than 20th on the grid, so Button and Alonso will also be hit by time penalties during the race.

Button said on Friday, before news of the penalty was confirmed: “I’m probably going to start at the back. And then Sunday, who knows? With penalties, you sort of really need a safety car to bring you back into the game. Hopefully that will be the case and we can race.”

Red Bull’s Australian Daniel Ricciardo and the Russian Daniil Kvyat, taking part in their “home” grand prix, also face 10-place grid drops following engine changes. Regulations stipulate drivers must make four engines last the entire season or pay a penalty.