Formula One today hit the track running in contentious style. Lewis Hamilton and Button have the option to close off a vent in the cockpit of their car using their legs, which gives them 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.

Button said "Our wing is our wing, and that's the way it is."

He went on to say "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, aerodynamically and with our straight-line speed we're reasonably happy with where we are."

Renault's managing director Bob Bell isn't so happy,"It is fundamentally clear that the McLaren wing design is totally illegal and that FIA is being 'ridiculous' in green-lighting the design."

FIA president Jean Todt said there would be no reversal over the decision to allow McLaren to use a controversial rear-wing design.