Motorsport boss Max Mosley has warned Formula One team owners they need to take radical measures to drag the sport out of a financial crisis.
Mosley says urgent steps need to be taken
Ford's decision to sell of Jaguar and engine supplier Cosworth puts 30% of the grid at risk.
Mosley, boss of the sport's governing body the FIA, described the situation as "potentially very serious".
"Costs are far too high and unless something's done, we're bound to lose teams, it's that simple," he said.
"Most money spent is wasted. Top teams can afford that but the others can't."
Mosley said he thought it would be easy to make savings without the visual spectacle of racing being damaged.
"There's no doubt F1 as a whole could run for less than half and probably closer to a quarter of what it currently costs without anything being visible from the outside," he said.
"Whether we can do anything about it quickly enough is another matter as any attempt to do something significant about cost comes up against resistance."
F1 supremo Bernie Ecclestone came up with the idea of teams putting out a third car to fill up the places, but Mosley rejected this as a short-term solution.
"I'm not at all sure they can put three competitive cars in the field because it will cost each of them significantly more so where's the money going to come from?" he said.
"I think everyone's going to sit down very carefully and decide what they will do."
Mosley blamed the resistance of F1 team owners to his plans to change the rules for 2005 for the crisis.
"The absolutely stubborn and entrenched opposition is
very frustrating," Mosley said.
"It is depressing to come and see what China has done and our response is to
say we maybe won't have 10 teams next season.
"It's not necessary. The problems are all soluble. You must be able to react. Two years ago it was obvious we needed to react.
"More than two years ago we started urging change and here we are."
However, Mosley did say he thought that the number of teams would remain at 10 in 2005.
"What I think is the most likely scenario... is that
someone will buy Jaguar, Minardi will keep going like they
always have and Jordan will find a solution in one way or
another," Mosley said.
"And we will have the same 20 cars next year. I think that's the most likely - I don't say it will happen - and then in 2006 I think we might see at least one and
maybe two new teams."