Christian Horner has ruled out a Red Bull move for Fernando Alonso by stating there is "no doubt" that Daniel Ricciardo and Max Verstappen will stay put.

Alonso's future has been the subject of speculation, as the two-time Formula One world champion has made no secret of his discontent with McLaren's inability to compete.

A switch to Red Bull does not appear to be an option for the Spaniard, though, as team principal Horner said there will not be any spare seats at the Austrian team next year.

"There is no doubt in my mind or anyone in the team's mind that they're not part of the team next year," Horner told told Sky Sports F1.

"The only driver who had a clause [at Red Bull] was Mr [Sebastian] Vettel. We're very happy with the drivers and they just want to go quicker.

"They are on junior driver contracts whereas Seb was able to renegotiate after his second world championship, which had a bit of performance in it which gave him the trigger when Fernando made his move from Ferrari. These drivers don't have that trigger."

Horner added: "We don't have space. It's a shame to see Fernando in the lack of competitive situation he is in, but there is no room at the inn within Red Bull."