The FIA is aware of teams exploiting diffuser regulations after approving a design related to the intrigue surrounding Williams and Toyota, autosport.com has learned, but the governing body has drawn short of confirming whether both teams' cars are okay.
As autosport.com reported last night, a number of teams are set to seek clarification from the FIA about the way that the diffusers on the Williams and Toyota cars appear, through clever use of the rear crash structures, to exceed the maximum height of 175 mm.
Renault executive director of engineering Pat Symonds told Autosport: "They (the diffusers) are certainly interesting, although I don't think I can comment on their legality.
"That's something for the FIA to comment on. We will be asking the FIA about it, but we haven't yet."
The Williams diffuser has a low centre section, well below the 175mm height limit, before a higher steeper element further back creates a second section around the rear crash structure.
The extra area of the Toyota diffuser is based in a 15 centimetre wide zone at the centre of the car where teams are allowed to fit extra bodywork. This has created a longer centre tunnel for air.
Although Williams and Toyota have not commented officially on the designs, sources from both teams suggest they are confident their designs are legal.
It is not clear when rival teams will contact the FIA about the Toyota and Williams designs, but a high level source at the governing body has confirmed that it is aware of the situation.
The source also said that approval for one diffuser design had been granted - although would not state whether it was a design that currently featured on any of the cars.
The source told autosport.com: "The FIA has had some correspondence with Toyota about diffusers but hasn't actually seen what they've been testing.
"One design has been approved by the FIA but we cannot confirm that it is the design in question."
Should the FIA confirm to rival teams that the design concepts of the Williams and Toyota cars are legal, then it may force a number of outfits to redesign the rear of their cars prior to the start of the season.