Red Bull have often promoted from within their own ranks. When Mark Webber retired at the end of 2013, it was Daniel Ricciardo who stepped up from Toro Rosso. And when Sebastian Vettel moved to Ferrari a year later, Horner again looked to the sister team, bringing in Daniil Kvyat. But could the team follow that path again?

George Russell’s camp and the Aston Martin rumours: what they want revealed

Verstappen’s teammate Yuki Tsunoda is out of contract at the end of the season, and has not at all convinced since replacing Liam Lawson. Isack Hadjar is in line for a promotion to Red Bull, but even he has cast doubt on his readiness for the Milton Keynes outfit.

While Helmut Marko sees Arvid Lindblad more as a long-term option, the young driver still needs to prove himself. Red Bull may have to look outside their own system for an established winner if Verstappen moves on.

According to Auto Motor und Sport, Horner feels he might need to sign Russell – quite a shift after the pair’s fallout last year.

Russell had criticised Verstappen’s driving in Qatar, and just recently joked about the Dutchman’s penalty situation in Canada. After Russell’s win there, Red Bull even filed a complaint about his conduct behind the safety car.

Despite these clashes, both Toto Wolff and Horner seem careful not to burn bridges. Wolff, in particular, has steered clear of criticising Verstappen, possibly keeping future options open.

Meanwhile, journalist Michael Schmidt has noticed that Horner speaks positively about Russell more often than one might expect. Given that Red Bull could need a new frontman, those comments might not be a coincidence.

Last year, Horner told reporters at the Singapore Grand Prix that Red Bull would be foolish not to consider a driver of Russell’s quality. And while Russell is expected to re-sign with Mercedes soon, the length of his new deal will be worth noting.

His last contract was just two years, a short enough span to keep options open for the future. With Red Bull watching closely, Russell spoke to Sky Sports recently: “If you are performing at your best and you stick with a team and you perform at your best, you don’t need to worry about anything else.”

It’s only two years since Russell replaced Valtteri Bottas and joined Lewis Hamilton at Mercedes. He’s since won four races and scored 20 podiums.