Fernando Alonso's F1 exit is "sad", but it's just part of the regeneration of the sport.

That is the view of Bob Bell, a top Renault official who was also with the French works team when it won titles with Alonso over a decade ago.

"It's very sad that Fernando is leaving formula one," he told Marca.

"It's even sadder that he leaves with only two titles, because it should easily be four or five. But it's also just the normal cycle of the drivers," Bell added.

"There are young and exciting talents coming to Ferrari and Red Bull next year, so it's the natural regeneration of the drivers."

Bell said he is looking forward to the arrival of Daniel Ricciardo next year, but he also admitted that Renault wanted to re-sign Carlos Sainz as well.

"It was a very difficult situation for us," he said. "If Red Bull exercised the option they had over him, there was nothing we could do. So when Ricciardo become a possibility we had to decide."

And Renault boss Cyril Abiteboul said the reason the team turned down Esteban Ocon was because of his Mercedes links.

"We have a serious issue that he is a Mercedes driver," he told Nice Matin. "We could work with Esteban in the short or the medium term, but he had to be only a Renault driver.

"Believe me, Esteban is very talented and he will certainly return to formula one," Abiteboul said.