Horner says that Ocon would not be considered by Red Bull for a Toro Rosso seat while he is contracted to a main rival, despite the lack of qualified young drivers within the drinks company’s own junior programme.

Both McLaren boss Zak Brown and Renault chief Cyril Abiteboul have expressed similar sentiments about Ocon, who will be without a drive when Lance Stroll joins Force India.

With Red Bull reluctant to hire drivers linked to other teams, former Red Bull and Toro Rosso driver Daniil Kvyat is believed to be top of the list for a return to the Faenza outfit.

For PRIME users: The bigger picture influencing the F1 driver market

“For what is relatively little investment by Mercedes it’s been to their merit that they’ve helped these guys to get into F1,” Horner told Motorsport.com. “But now it seems to be almost an anchor being a Mercedes driver.

"Being on a recall mechanism isn’t attractive to a vast majority of teams.

“The crazy situation is you’ve got a driver like Ocon who might end up without a seat next year. If he was to be contractually free he’d be an obvious candidate for Toro Rosso.

"But Red Bull aren’t going to invest in a Mercedes driver, understandably. And I wouldn’t expect the same to happen the other way round.”

Mercedes should have taken risk on Ocon

Horner said that Mercedes could have solved the Ocon problem by promoting him to a race seat with the works team, pointing that Red Bull had taken the plunge with Sebastian Vettel, Daniel Ricciardo and Max Verstappen.

“It’s very easy to go with something known," he said. "And there’s far more perceived risk in taking an unknown quantity or a junior, and I think we’ve demonstrated on numerous occasions that it pays off.

“We’ve had a very successful junior programme, and Red Bull has a junior team, and has invested in that. It’s paid dividends with Seb, Daniel and Max, and we’ll see with Pierre Gasly [who replaces Ricciardo in 2019].

"And it’s given numerous others opportunities, such as Carlos Sainz.”

Horner acknowledged that there is currently a “window” just below F1 in Red Bull’s talent ladder, but he stressed that there are plenty of youngsters on the way up.

“The market place goes in fits and starts," he continued. "We’ve got Dan Ticktum in F3 who’s winning that championship, but these things are all cyclical.

"We’re constantly looking at young talent and emerging talent, so I don’t think that window will be open for too long. We’re looking at the grass roots, investing in youth.

"We have two very good young junior drivers on karting at the moment, Harry Thompson and Jonny Edgar. You have to go to the grass roots to try and support young talent coming through.”