Horner believes 21-race calendar is already too long

Red Bull team boss Christian Horner believes the current Formula 1 calendar is too long and has warned against Liberty Media further adding to it.

Horner explained how the effort required by the teams during the Grand Prix weekend lasts more like a week, and that it would be detrimental to the sport to make the calendar even longer.

He said: "I think what you have to appreciate is that a grand prix weekend, not for us but the people down in the garage, it’s a week-long event.

"For many other functions that are involved in going to grands prix, 21 is already a big ask. Going beyond that is, I feel, a tipping point.

"You then have to look at the construction of the grand prix weekend. Do we need to do as much testing as we do? The duration of the season.

"All those factors and what impact it has on cost and budget caps and so on and, is it ultimately going to make it a better show?"

F1 has already announced that a Vietnam GP will be introduced next year, with rumours of a second Chinese race and a Dutch GP to come…