Jul.3 (GMM) Jenson Button's stalled formula one career is leading to questions about his motivation.

John Surtees, also a Briton who raced in formula one for Honda in the 60s, told a Swiss publication this week that 28-year-old Button is a "big question mark" in his mind.

After more than 100 attempts, Button won his first grand prix in 2006, but in the past two years his machinery has not been up to speed.

1964 world champion Surtees said in interview with Motorsport Aktuell: "He seems to be having problems with his motivation."

Also this week, David Coulthard - one of Button's on-track rivals who is also a close friend - joked that the wavering form of F1's other Britons is giving him reason to contemplate victory at Silverstone this weekend.

"Lewis is looking a bit shaky right now with all these penalties and pitlane crashes. Jenson just seems to be cruising. I'm going to have to step up," he is quoted as saying by The Daily Telegraph.

Button denies he is struggling with motivation and is looking forward to 2009, when Brackley based Honda could be more competitive.

"I'm in a happy place," he told the BBC.

"Hopefully the fans aren't too frustrated because I feel pretty happy with the situation," Button added.