Christian Horner: Vettel is struggling to carry Ferrari's hopes

Credit: PA

Sebastian Vettel is feeling the heat in Ferrari's "pressure-cooker environment", Red Bull team principal Christian Horner has claimed.

It is 300 days since the four-time world champion last won a race, and he arrived for Sunday's French Grand Prix following yet another mistake, which ultimately cost him victory in Canada a fortnight ago.

When in wheel-to-wheel battle with rival Lewis Hamilton, the Ferrari driver has made a number of errors.

He ran off the road while leading in Montreal. He spun in Bahrain earlier this season, and Monza last year, too. There have also been further mistakes which have scuppered his recent championship challenges.

Vettel missed out on first place in Canada due to a penalty. Credit: PA

Ferrari have not won the drivers' title since Kimi Raikkonen triumphed in 2007. Vettel was hired from Red Bull to end the Scuderia's barren run.

The 31-year-old German won four consecutive championships, and 38 of his 52 career victories, driving for Red Bull.

"With us, Sebastian was like a metronome when he was in the lead of a grand prix," Horner told Press Association Sport. "He was always so strong in that position.

"He obviously looks a lot more under pressure these days as he is carrying the hopes of Ferrari in what looks like a pressure-cooker environment."

Vettel and Horner worked together at Red Bull where the German won four World Championships. Credit: PA

Vettel's deal with Ferrari expires at the end of next season, and in the aftermath of his penalty in Canada, he said he had fallen out of love with Formula One.

Here, when asked how he can change the sport to avoid further penalties, Vettel joked: "Retire. At least then I am not in trouble anymore."

So, is there a danger that the third-most successful winning driver in Formula One's history might walk away from the sport?

"Sebastian is very much his own man," added Horner. "He is a fan of the history of the sport, and like anybody, when you enjoy what you are doing, you do it that much better.

The pressure is on again this weekend in France for Vettel and Ferrari. Credit: PA

"Certainly the years that we had at Red Bull were always a lot of fun. Even when we were competing hard against formidable rivals there was always a fun factor to it.

"To get the best out of people, you have got to deliver the right environment for them - that is so important."

Vettel's first win of the season was chalked off after he was controversially adjudged to have rejoined the track in front of Hamilton in a dangerous fashion. Ferrari's bid to have the punishment reviewed was thrown out by the FIA on Friday.

Horner added: "It was a shame that it ever ended up in front of the stewards. We have been trying to encourage racing and fewer penalties. They are such a turn-off to the casual viewer.

"The rules need a degree of interpretation, and that is why we should have a permanent steward or referee who is able to show discretion as to what is a racing incident and what isn't."