Mat Coch writes:

Red Bull will be forced to run a revised floor and diffuser following a decision by the FIA outlawed the design the team has run since Bahrain.

In a decision handed down late on Friday night, the sport's governing body outlawed holes in the floor ahead of the rear wheels, effectively banning the design Red Bull has been using in recent races.

The decision does not put at risk the wins in Bahrain or Monaco however, it does mean the Milton Keynes outfit will have to change its cars ahead of next weekend's Canadian Grand Prix.

"Following on from a number of discussions in Monaco, during which it became clear that certain misunderstandings existed, we feel it would be helpful to make our position clear with respect to the presence of a fully enclosed hole in any surface lying on the step plane," a note from the FIA to teams said.

"It has been argued that, as it is not explicitly stated that fully enclosed holes cannot be located in a surface lying on the step plane rearward of a line 450mm forward from the rear face of the cockpit template, then they may be located in such areas.

"We disagree with this view and consider it implicit that fully enclosed holes may not be located there," the note declared. "If they were permitted the opening part of the second paragraph of Article 3.12.5 (which was added to the regulations at the same time as Articles 3.12.9 and 3.12.10 for 2011) would be superfluous).

Mercedes, Ferrari and McLaren were all unhappy with Red Bull's solution in Monaco and had threatened to protest. While that protest never came about this ruling is confirmation that the system was illegal, despite the fact that no retrospective action against the team is expected.