Red Bull in technical controversy just before Monaco GP

Champions Red Bull were embroiled in a technical controversy before Sunday's Monaco Grand Prix with suggestions that their cars could be in breach of the regulations.

Formula One sources indicated that a protest was likely after the race with attention focused on an apparent hole in the step plane of the floor of the car.

The governing International Automobile Federation (FIA) was aware of the situation.

Red Bull team principal Christian Horner was convinced that the car was legal and ruled out any pre-race changes, which would entail a grid penalty, pointing out also that it had passed pre-race FIA scrutineering in Monaco.

"There was a bit of a fuss after the Bahrain race, but it was clear the car complied," he said.

"We sought clarification after that, but there is no doubt the car is fully compliant."

Red Bull, who have Australian Webber on pole alongside Mercedes's Nico Rosberg while Red Bull's double world champion Sebastian Vettel is ninth on the grid, have used the same floor for the past three races.

The team won in Bahrain, with Vettel.

The Formula One technical rules stipulate that cars cannot have holes, which would produce aerodynamic benefits, in certain areas of the floor.

"There are other cars running in similar situations," said Horner. "As I say, we're totally comfortable with the car and that it complies with the regulations."