Jenson Button's Formula One world title chances have been questioned by Spykyer technical boss Mike Gascoyne.
Button has won just one race in seven seasons in Formula One
Gascoyne, who worked with the Honda driver in 2001 and 2002, doubts the Englishman has the ability and spirit to ever win the drivers' crown.
He said: "Fernando Alonso won the title when the car wasn't at times quickest - does Button have the craft and ability to do that? That's a question mark.
"He is a race winner, but it's whether or not he's a championship winner."
Gascoyne worked with Button at Benetton in 2001 and again the following season when the team was renamed Renault.
He believes Renault made the right choice when they promoted test driver Fernando Alonso in place of Button, who left to join BAR, who were bought out by Honda before the 2006 season.
If Hamilton gets beaten in every race by Alonso, his confidence will go
"I agreed with team boss Flavio Briatore when he replaced Button with Alonso," said Gascoyne.
"I think Alonso had the spark that made him stand out."
Button made a significant breakthrough in Hungary last season when he won his first Grand Prix in 113 attempts.
But Gascoyne does not think the 27-year-old has improved enough to mount a serious challenge to double world champion Alonso, now at McLaren, and Ferrari's Kimi Raikkonen in 2007.
He said: "Button got the monkey off his back last year, but Honda can't help but to talk themselves up at the start of the year.
"You've got to wait and see how competitive the car is. He's proved that if the car's there then he'll deliver."
Gascoyne is highly regarded within F1 after he turned round Renault and Jordan
Gascoyne, who joined Spyker after leaving Toyota in April, also fears Britain's rising star, Lewis Hamilton, could suffer under Alonso's shadow this season.
Hamilton, 22, will drive alongside Alonso at McLaren in his debut Formula One season after coming through team boss Ron Dennis' development programme.
"Hamilton is under huge pressure, especially with Fernando Alonso alongside him," said Gascoyne.
"It's a big ask for a young man at McLaren and if he gets beaten in every race by Alonso, his confidence will go and it will be very difficult.
"It's a very difficult situation, but I think that Ron is the sort of person who will be very supportive if he struggles."
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