Red Bull motorsports consultant Dr Helmut Marko is renowned for discovering the talent of Sebastian Vettel at a young age through the team's driver development programme.

But many other drivers who have come into Formula 1 via the same route have not had such glittering careers. And Marko is just as well known for ruthlessly dropping any drivers he feels are not living up to expectations.

The most recent example is Daniil Kvyat, who started at Toro Rosso in 2014 after winning the GP3 title. He was promoted to Red Bull in 2015, demoted back again the following season, and finally dropped by the squad at the end of 2017.

Kvyat's experience seems to be a warning sign for at least one young driver still hopeful of making it into F1.

"Of my own volition I would not sit in the Toro Rosso," Renault development driver Artem Markelov told Sport FM this week.

"Knowing Dr Marko, knowing how he ruins the careers of young drivers, I don't need that," added the 23-year-old, who currently races for Russian Time in Formula 2.

Markelov is one of the names being linked to a seat at Red Bull's junior team, if it decides to drop current driver Brendon Hartley from the line-up.

Hartley was a surprise call up to the team for last year's United States Grand Prix. While the Kiwi had previously been a part of the Red Bull driver programme, he was axed by Marko in 2010 in favour of Jean-Éric Vergne.

Hartley was recalled and handed his F1 bow after being part of Porsche's winning team at last year's Le Mans race. But in nine races he's managed to finish in the top ten just once, in Baku.

"It's very hard to get to Formula 1 and even harder to stay there," Sky Sports commentator Martin Brundle told New Zealand's Radio Sport. "It's a brutal place in the Red Bull hierarchy as he knows, because he's already been on the receiving end of it.

"I suspect there are some concerns to his absolute pace and issues he's been having," Brundle added. "He does need some decent results.

"Pierre Gasly is doing good job in the other car and it's inevitable vultures will be circling if they see someone having a bit of a difficult time."

Former Sauber driver Pascal Wehrlein is one of the drivers tipped to take over from Hartley. But Wehrlein is a product of the rival Mercedes development program, which may count against him.

Markelov's backing from Renault could give him an advantage. Currently, Carlos Sainz is on loan from Toro Rosso to the Renault works team, making a bit of quid pro quo possible.

"Would I agree to go in the place of Hartley?" mused the Russian. "If Renault gave the go-ahead it's possible."

However Markelov also had other concerns about heading to Red Bull or Toro Rosso in the near future.

"There are also rumours that Christian Horner could leave Red Bull," he pointed out. "And that Red Bull wants to leave Formula 1.

"They're just rumours. But I don't know what the prospects of being at Toro Rosso and Red Bull are," he said.

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