Red Bull team boss Christian Horner believes Sebastian Vettel has chosen the right time to retire from Formula 1, saying it is “not nice to see” him running in midfield.

Vettel announced prior to last month’s Hungarian Grand Prix that he would retire at the end of this season, ending a 15-year career racing in the series.

Vettel linked up with Horner when he was promoted to the Red Bull team in 2009 after a stint at its sister outfit Toro Rosso, and thus began one of the most successful partnerships in F1 history.

After finishing runner-up to Jenson Button in his first year at the team, Vettel went on a run of four consecutive drivers’ championships between 2010 and 2013.

While a difficult final year at Red Bull saw him leave for Ferrari in 2015, Vettel retains a good relationship with his former Red Bull colleagues – with Horner opening up on his former drivers impending retirement.

“He was a pleasure for us to have in our team,” said Horner, as quoted by Motorsport.com. “We achieved some great things together. I think having just watched him grow from a boy into a young man, he’s a very principled guy. He has very strong beliefs.

“We’ve seen that in the latter stages of his career, as he’s very much standing up for things that he feels passionate about, and rightly so. His family is important to him. He’s a very private man. So pleased to see he’s become an Instagrammer recently!

“And while his F1 career comes to an end, he’s got a lot that I’m sure he wants to do in his life. And I’m sure he’s going to go on and do some great things. It’ll be sad not to see him around. But I think the timing is right for him.

“It’s not nice to see him running around in the middle of the field, he doesn’t deserve to be there. And I think the time is right for him to say, ‘Now’s the time for me to call time on F1’.”

Aside from four straight titles, Vettel won 37 races for Red Bull during his six seasons with the team, showing a tremendous attitude and commitment on and off the track according to Horner.

“I think the thing that stood out about Seb, was from the very beginning, you could see he was a very focused young man, and his work ethic was totally Germanic,” he said.

“He worked hard, he worked late, and he had a great sense of humour, so fitting into a British team, he embraced the culture immediately.

“He endeared himself across all areas of the business, whether he was turning up with chocolates for secretaries or learning the lingo in the garage – his command of cockney slang became legendary.

“He was formidable in the cars that we produced in that period of time. They were halcyon days in F1 – massive competitors, big teams that we were up against, and some outstanding successes.

“He, at that stage, was very focused on achieving not just success, but achieving and going for records. They meant a lot to him.”

Reflecting on those championship-winning years, Horner felt Vettel became a better driver over his spell at the Milton Keynes-based team, citing 2013 – when he won nine races on the bounce – as his “pinnacle year”.

“He just got better and better,” said Horner. “I mean, in 2009, we were a young team, as well as him. And we made a few mistakes. In ‘10, he was the standout driver that year, had a lot of unreliability, and against the odds won the championship at the end of the year.

“In ’11, he built on that. ’12 was a super tough year. He’d only won one race before we left Europe. And then won, I think, four on the bounce to go head-to-head with Fernando [Alonso] in that final race in Brazil.

“By the time we got to ’13, he just absolutely dominated, and then nine victories in succession that he achieved, that was that for me was his pinnacle year. He brought everything together and was just truly outstanding that year.”