Mat Coch writes:

The FIA has confirmed its intention to outlaw blown diffusers from next month's British Grand Prix. It was announced ahead of the Spanish Grand Prix that the governing body intended to ban the practice before backing down in the face of logistical and financial concerns from the teams.

Teams have been directing exhaust gasses to increase downforce, using elaborate engine mappings and exhaust layouts to direct exhaust flow underneath the car, even while the drivers are off the throttle. "An exhaust system is there for the purpose of exhausting gasses from the engine and when you're off-throttle it isn't doing that anymore," said the FIA technical delegate Charlie Whiting. "It's being used to influence the aerodynamic characteristics of the car. We think, arguably, this infringes Article 3.15 of the technical regulations."

A letter from the FIA to teams this weekend has confirmed its plans to enforce the ban from Silverstone. Its understood the FIA will also meet with the teams' Technical Working Group on Thursday to discuss further restrictions with a view to introducing them next season.

"The FIA has made its position very clear," said Williams Technical Director Sam Michael. "They want to talk about the fine details on Thursday, but what Charlie (Whiting) is saying is that hot blowing is banned and cold blowing is banned from the Silverstone GP onwards.

"For 2012, the exhaust system must exit behind the rear wheel centre line, actually 330mm behind, so right out the back of the diffuser. That means there cannot be any exhaust influence on the diffuser. That is what the FIA has clarified and then Thursday is about implementation."

Mercedes team boss Ross Brawn told the BBC that, while qualifying pace will likely be affected, race pace is unlikely to suffer unduly as a result of the ban. "Unless the teams can show a definite major problem with the approach that means it's not feasible, it will go ahead," he said. "In qualifying, it means a lap-time deficit of half to one second, although our race modes aren't going to be that different."

It's believed Red Bull is the biggest exponent of the blown diffuser concept, some teams suggesting its use explains the advantage the Milton Keynes squad enjoys during qualifying.