Motor sport's world governing body have confirmed the case will go in front of three independent judges in Paris on April 14, with Red Bull, Ferrari and Renault up against Brawn GP, Toyota and Williams.

Although a protest was thrown out by race stewards presiding over the Australian Grand Prix this weekend, the aggrieved trio maintain their rivals failed to adhere to the regulations regarding the design of their diffuser, a key aerodynamic component that governs the airflow beneath a car.

It became apparent yesterday that Brawn GP, Toyota and Williams have an advantage as they claimed six of the top seven fastest times in practice.

Asked whether that was a coincidence, Horner said: "I don't think there is.

"I think that interpretation (of the design) offers a performance advantage, so inevitably all of the teams, if that solution is now permitted, will all go off and pursue different variants of it."

It that apparent advantage is maintained in tomorrow's race, and next weekend's in Malaysia, F1 faces becoming a two-tier title battle.

"You could even say it is three tier - those with KERS and those without, and those with double-decker diffuser and those without," added Horner.

"It is a shame the FIA has ruled their cars are legal. We obviously have the right to appeal that.

"But we are here to go racing and we'll do the best job we possibly can. Hopefully we can be as close to the front as we can be."

Horner has admitted work has already started on a 'copycat' design if the diffuser used by their rivals is deemed legal.

"You cannot afford to wait, so effectively we have already had to start looking at alternative solutions," confirmed Horner.

But for Red Bull and the other six teams, it is not as simple as simply constructing a new bodypart and applying it to the car.

"It depends how far you want go with it," added Horner.

"Potentially it involves significant amounts of time if you were to really optimise to an extreme point - and potentially it involves half of the car.

"So it is not a quick or cheap solution."

The furore has led to suggestions it could split the Formula One Teams' Association (FOTA), the umbrella organisation created last year, and under which the 10 marques conform.

Prior to this week the teams have been cohesive in relation to the future of the sport, in particular in their battle with the FIA on certain issues of late.

However, BMW Motorsport director Mario Thiessen has confirmed there is no rift in FOTA, insisting: "No, not at all.

"We have discussed this openly between the FOTA members.

"There is a clean line between moving forward jointly in order to shape the future of F1 from our perspective on one hand, and on the other hand there is the daily operational basis which is competition and this (diffuser row) is one of the second issues."

FOTA vice chairman John Howett added: "I can't understand it is anything to do with FOTA.

"In FOTA we talk about long-term strategic issues for developing the sport for the future, things that are right.

"Racing is racing, and under racing it is perfectly understood that a team can protest another team if they consider they have valid grounds to do so.

"We don't have any negative feeling as a team that could be protested. It is part of the sport we are in."