The future success of Formula One depends on a solid core of independent teams rather than car makers, according to the president of the sport's governing body.

International Automobile Federation (FIA) chief Max Mosley said manufacturers could not be relied upon to contribute to the long-term future of the sport.

"Although their presence is very welcome, the car manufacturers will come and go as it suits them - they have always done this and they always will," he said.

We can rely on the independent teams.... we cannot rely on the manufacturers FIA president Max Mosley

"After all, they are responsible to their shareholders, not to motorsport."

Mosley has been pushing for changes which would reduce the cost of running an F1 team, particularly after the 2002 demise of independent teams Prost and Arrows.

But the seven manufacturers have upset him by opposing the planned alterations.

In an open letter, Mosley proposed that from 2004 teams should be limited to one engine per car per weekend and that from 2005 engines must last two races.

By 2006, he plans to have teams use one engine over six races.

Patrick Faure is not happy with the proposed changes

He estimated that an independent team's outlay for engine supply could drop from its current cost of over �12m to less than �1m in 2006.

"This is still very expensive, but it is probably manageable," he said.

Mosley concluded that if costs came down, the sport would be able to survive the possible departure of some manufacturers.

Car makers have already expressed their opposition to the six-race engine.

Renault boss Patrick Faure said the French manufacturer would quit the sport if such a "tractor engine" were introduced.

"The plan for an engine for six races is the end of Formula One," he said.

"We will not stay in the championship with these kind of rules, clearly, none of us."