JENSON BUTTON shrugged off the controversy surrounding the new McLaren as Formula One yesterday hit the track running in typically contentious style.

A debate is raging regarding an innovative aerodynamic concept on the car that has been passed legal, but has had nearly every other team principal and engineering guru mumbling words of discontent.

The design employs Lewis Hamilton and Button to close off a vent in the cockpit of their car using their legs, which in turn helps to stall the rear wing for extra straight-line speed.

As it is the drivers doing the moving, rather than any part of the car, which would be illegal, FIA race steward Charlie Whiting has given the McLaren the all-clear.

Following two practice sessions ahead of the seasonopening Bahrain Grand Prix, reigning champion Button and 2008 king Hamilton were on the pace, finishing fourth and second-quickest respectively behind Mercedes GP’s Nico Rosberg, with Michael Schumacher third.

Button was coy when asked about the device before adding: ‘‘Our wing is our wing, and that’s the way it is.

‘‘There’s no problem with it as it’s been passed by the authorities.

It’s an innovative design and it seems to be working well.

‘‘We all want more downforce, but aerodynamically and with our straight-line speed we’re reasonably happy with where we are.’’ Renault’s managing director Bob Bell has been one of the most outspoken critics of Whiting’s decision, pointing an accusing finger at the FIA.

‘‘It is fundamentally clear the McLaren wing design is totally illegal,’’ complained Bell.

‘‘They have driven a cart horse through the spirit of the rules and regulations. They have opened up another arms race.

‘‘It’s going to cost everybody a lot of money. The governing bodies need to be a lot stronger with these things.’’ The device is not as controversial as last season’s rear diffuser row that sparked a war between the teams and culminated in an FIA hearing to resolve the matter.

Although it is unclear whether any protest will be launched, it will not be Renault leading the cause as they would not want to rock the boat.

The team is currently operating under a two-year suspended permanent ban from the sport in the wake of the ‘crash-gate’ hearing.

Under FIA rules, if there is a protest, it has to be made shortly after the conclusion of tomorrow’s race, with the suggestion at the moment that one team is willing to test the water.

The likes of Red Bull Racing’s Christian Horner and Mercedes GP’s Ross Brawn are of the same mind, that they will have to find their own method on this matter.

Horner, who was the first to raise concerns over the McLaren wing, said: ‘‘We obviously questioned it some time ago.

‘‘But the FIA have looked at it and deemed it to be okay. It’s therefore a clever design rather than an illegal design.

‘‘The question is, is the driver part of the car? They deem him not to be.

‘‘Inevitably now there will be a wild goose chase of all the teams chasing that loophole.

‘‘We have to come up with another solution. Anything’s possible.’’ Brawn, who last season sparked the diffuser controversy that aided his team’s runaway start and subsequent championship successes, is also looking into developing a similar aid.

‘‘We will have to get on and make our own version of it now,’’ said Brawn. “We have had clarity from the FIA about how they want to treat it, so we are all off running in that direction.’’ For new teams like Lotus Racing, already a considerable distance off the pace, the issue has left chief technical officer Mike Gascoyne perplexed and angry.

‘‘Whether the driver is doing it with his knee or not, they (the aerodynamics) are not the same all the time, so therefore it must be a moveable aero device,’’ remarked Gascoyne.