LONDON, England - Formula 1 World champion team Red Bull must modify the floor of its cars for the 2012 Canadian GP after the sport's governing body issued a formal clarification of the rules.A spokesman for the governing International Automobile Federation said race director and technical head Charlie Whiting had sent all teams a directive on Friday following allegations that the Red Bull floor had an illegal hole.The argument in question is arcane even by F1 standards, with technical experts arguing over "fully enclosed holes", the difference between a "hole" and a "slot" - even what constitutes "a hole".CONTROVERSY, BUT NO PROTESTSuch holes can produce aerodynamic benefits and, in his note, seen by Reuters, Whiting set out what was permissible.He said: "Following 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."The controversy erupted only hours before May 2012's Monaco F1 GP with Australian Mark Webber starting on pole for Red Bull. Rivals had appeared set to protest about the Red Bull's floor which, they argued, had an illegal "fully enclosed hole" on the surface of the step plane of the floor.In the end there was no protest and Webber celebrated his first win of the season - and Red Bull's second - but the FIA was aware of the situation and acted anyway.The FIA directive 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 of 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."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."RED BULL ADAMANTRed Bull, leading McLaren in the Constructors' standings by 38 points after six of 2012's 20 races, has been adamant that its floor is legal and rebuffed doubts in Monaco. Team principal Christian Horner said at the time: "There was a bit of a fuss after the Bahrain race (won by Red Bull's Sebastian Vettel in April) but it was clear the car complied. "We sought clarification after that but there is no doubt the car is fully compliant."Red Bull was not immediately available for comment on Saturday, the start of a four-day holiday weekend in Britain to celebrate Queen Elizabeth's Diamond Jubilee marking 60 years of her reign.