Red Bull rubbishes Verstappen to Ferrari rumours

Horner is adamant that the Dutchman is contracted to Red Bull for the foreseeable future, and says there has been no approach from the Verstappen camp about a possible move.

"No, not at all, never at any point in time, or any suggestion of it," he told Motorsport.com. "The agreements are very clear.

"We know what our driver line-up is for next year, and that's what we're working and planning around. Anything else is pure speculation or mischief-making."

Horner also denied that it might be easier for Verstappen to engineer a move in 2019.

"Not necessarily. At the moment we're focussed on this year and next year," he added.

The team boss insisted he wasn't concerned about the ongoing speculation being a distraction.

"It's a little tedious, but we know what the situation is. It doesn't change anything."

Horner said on Friday that Daniel Ricciardo's win in Baku had not made any difference to the contracts of the drivers, meaning it didn't trigger a performance clause that locked them in to their current deals.

"It doesn't make any difference to the contracts," he said. "We're very clear on what our drivers and who our drivers are for next year, which are the same numbers that are on the car this year.

"So there's nothing really to report on that. The contracts are clear, so both drivers are under contract for next year, 100 percent."