Mark Webber has hit out at the suggestion that the Red Bull he drove to victory at the Monaco Grand Prix was illegal in a passionate statement ahead of this weekend’s Canadian Grand Prix.

Both Red Bull cars had been running with holes on the floor just in front of the rear wheel since the Bahrain Grand Prix, where the system passed FIA inspection. Rival teams, including McLaren and Ferrari, had unofficially raised the issue of whether it was legal at Monaco but made no formal protest.

A week later, the FIA issued what it termed as a “rule clarification” declaring the design illegal, although Sauber and Ferrari use a similar system but with a gap on the floor’s edge that allows it to be designated as a slot.

“In relation to winning races with an illegal car, I am happy to be called lots of things and to have criticism about my driving, but I will not stand criticism in that respect,” said Webber.

“It really [angers me] because it has passed every single technical regulation. All the teams who were against it did not make any protest after Monaco. The car passed the test after Bahrain, the car passed the test after Monaco and now there has been a new interpretation of the rule.”

Despite, as Webber noted, the design having been declared within the rules by FIA technical delegate Charlie Whiting, the clarification ahead of the race in Montreal was almost certainly made to forestall continued debate and even potential formal protests from other teams.

Webber, however, was optimistic the Red Bull would remain competitive in Canada. “We had a car that was legal for the first part of the season,” he said. “Now that rule has changed and we will start again, so I am looking forward to it.

“We are very optimistic that the change won’t affect us at all. You won’t believe this but we had changes for Valencia anyway, which included no holes, irrespective of the rule changes.”

Britain’s Jenson Button, who took a stunning win by overtaking Sebastian Vettel on the final lap here last year after a four-hour rain-affected race, but who has finished in the points only once in the last three races, was also optimistic about his chances for the world championship despite being in seventh place, 31 points behind leader Fernando Alonso.

“I purposely haven’t looked at the championship points in the last few races,” he said. “But I don’t think anyone is streaking ahead in the championship. But in the last few races I have retired twice and I have scored two points in the other one. They haven’t been my finest weekends so I need to score some good points here this weekend.”

Meanwhile, the traditional Thursday open day at the Circuit Gilles Villeneuve was cancelled after fears of disruption by students protesting against tuition fees targeting the race for publicity purposes.

Organisers remain concerned that protesters will attempt further action over the weekend and, although representatives of the students have stated that they will not disrupt the race itself, they may target underground stations which would cause considerable difficulties for fans travelling to the circuit.