In-depth interview: Max Mosley with BBC Sport's Adam Parsons
Formula One has been told it needs to implement drastic cost-cutting measures by 2010 if it is to remain "credible".
FIA president Max Mosley told BBC Sport that the global credit crisis had only exacerbated problems for F1 and several teams were now in danger of quitting.
"It has become apparent, long before the current difficulties, that Formula One was unsustainable," said Mosley.
"It really is a very serious situation. If we can't get this done for 2010, we will be in serious difficulty."
Mosley said there was a very real threat that some of the smaller independent teams would be forced to withdraw from the sport because of spiralling running costs.
"At the moment we've got 20 cars," said Mosley. "If we lost two teams, we'd have 16. (If we lost) three teams (we'd have) 14. It then would cease to be a credible grid."
The days when they could just toss out the 100, 200, 400m euros a year, which is what Formula One costs those big companies, I think they are finished
Mosley claimed the smaller teams needed vast sums of money just for the privilege of taking on the big manufacturers like Ferrari, McLaren and BMW.
Even then, he said, some of them were struggling to make an impression at the back of the grid.
"It depends at the moment on millionaires - billionaires, we don't have millionaires now - subsidising it, people like Vijay Mallya of Kingfisher (Force India) or Dietrich Mateschitz of Red Bull (Racing)," Mosley told BBC Sport's Adam Parsons in an exclusive interview in Paris.
"Without them, those teams wouldn't be there."
But Mosley warned that even the major players were beginning to feel the financial squeeze.
"The days when they could just toss out the 100, 200, 400m euros a year, which is what Formula One costs those big companies, I think they are finished," he said.
Mosley, 69, said one of the areas where costs could be reduced was the "drive-train" - the group of components that generate power and transfer it to the track, including the engine and gearbox.
"If you can believe this, the engine and gearbox together for an independent team is upwards of 30m euros a year," he said.
"That could be done for probably 5% of that cost without the person in the grandstand noticing any difference at all.
"Even those big spenders, if they are given the opportunity to save 100 or 200m euros a year will do so."
Mosley warned: "We've got various means of making sure they don't spend that money, but it does mean some draconian changes."
The FIA has given Mosley the power to negotiate directly with the Formula One Teams Association over proposed measures to cut F1 team costs in half by 2010.
If no agreement was reached, the FIA said, it would enforce its own measures.
The FIA has also agreed to allow Formula One teams to equalise engine performance across the field for 2009, pending the introduction of cost-saving measures from 2010.
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