Red Bull Racing boss Christian Horner says that Mercedes needs to make a decision about which driver to support in the title race.

Valtteri Bottas remains in contention for the world championship in third position, between leader Sebastian Vettel and Mercedes team-mate Lewis Hamilton.

Vettel’s Ferrari team-mate Kimi Raikkonen is a distant fifth, leaving the team with an obvious choice to back the German.

Mercedes, however, has not committed to either of its drivers yet, as demonstrated by Hamilton letting Bottas return to third position in the Hungarian Grand Prix after the Finn had earlier let the Brit through in the hope he could unseat the Ferraris.

Horner believes that approach cannot last, and he expects Hamilton to be the driver that will take the fight to Vettel.

“The dilemma that Mercedes have got is that Hamilton is their lead driver and at some point you have to back a horse,” said Horner.

“Ultimately it will probably come down to those two guys (Hamilton and Vettel), and Ferrari’s position with Kimi was far clearer.”

Horner added that he was impressed with Hamilton’s commitment to giving the place back to Bottas, despite the fact the second Mercedes had fallen nearly eight seconds adrift by the start of the final lap.

Asked if he was surprised Mercedes swapped places at the end, Horner said, “On the one hand yes, but on the other hand, it would have been harsh on Valtteri, because you are effectively telling him you are out of the championship the moment you did that.

“I was impressed Lewis gave it back, because you are just giving away more points to your biggest rival.

“We did it in Monaco two years ago (with Daniil Kvyat and Daniel Ricciardo) but it is slightly different when you haven’t got a driver competing for the world championship.”