Williams plays down diffuser ban claim.

The Williams team has reacted strongly to speculation that its rear diffuser may be banned before next weekend's Austrian Grand Prix.

Sources outside the Grove team confirm that a protest has been lodged with the FIA regarding the item, but refused to clarify whether these surrounded its size or constitution. Suspicion points towards excessive flex in the diffuser which, since the cutback in wing sizes, has once again become the focal point for aerodynamic performance.

Following Ralf Schumacher's unexpected win at the San Marino Grand Prix, attention has switched to the FW23 and why the team is managing to match perceived favourites Ferrari and McLaren on a regular basis. Although the diffuser has been passed by the scrutineers at each of the five races so far held this year, it is understood to be 'outside the spirit of the rules' rather than the letter of the law.

"We've been running within the regulations up to and including Barcelona, and we will continue to do from Austria onwards," technical director Patrick Head told the BBC's Ceefax service.

Neither Williams nor the FIA were willing to shed any further light on the speculation when contacted by Crash.net, although drivers Ralf Schumacher and Juan Montoya, as well as engineer Sam Michael, confirmed that aerodynamic development had been carried out on the car during the second day of testing in Valencia yesterday.