Ross Brawn insisted his team are innovators rather than cheats as he endured a grilling in the diffuser row hearing.

Brawn was pointedly described as "a person of supreme arrogance" as Formula One's newest team boss came under fire at one stage during the International Court of Appeal hearing in Paris, with a verdict due on Wednesday, although their full findings are not due to be revealed until either later this week or early next.

At stake are the race results in Melbourne and Sepang as the judges have the power to overturn them, although such an eventuality is not expected.

But the Brawn GP head stood his ground as personal slurs and the weight of the FIA regulations were thrown at him at motor sport's headquarters overlooking the Place de la Concorde.

FIA technical director Charlie Whiting was also forced to endure a 75-minute cross examination as he and the organisation were accused of "getting it wrong, and not understanding the point".

The brickbats were hurled during a marathon sitting that lasted over eight hours as Ferrari, Renault, Red Bull and BMW Sauber squared up to Brawn GP, Toyota and Williams in front of five ICA judges.

At the heart of the matter is the conceptual design of the diffuser - an aerodynamic body part that aids performance - towards the rear of the cars belonging to the three teams in the firing line.

Central to a 'double-decker' design are two apertures that assist airflow, so increasing downforce, which in turn results in greater speed. Reference was made to the fact that it was a new approach, and therefore had to be ratified by the FIA before being applied to the car.

But a defiant Brawn said: "We didn't consider this to be a radical new design.

"It was an innovative approach of an existing idea, and Formula One is all about innovative design. It's a cornerstone and objective of the sport."