FORMULA ONE:WILLIAMS WOULD rather see Formula One teams run three cars each than relax the rules on so-called "customer teams" to boost the numbers, chief executive Adam Parr said yesterday.

Honda's withdrawal from Formula One and the possibility that another manufacturer could also quit before the start of next season, has raised concern about the number of cars on the starting grid next season.

After starting with 11 teams in 2008, Formula One is down to nine without Honda. If another goes, that would leave 16 cars.

"There is the scope for teams to put three cars on the grid and if we have eight teams with three cars, that's 24 cars - which is four more than we have had this year," said.

"Even if we went to seven teams, we'd have 21 cars. My opinion is it is far better to have seven or eight constructors than seven or eight constructors and three or four customer teams," he added.

"Williams would rather compete on equal terms with constructors and take our chances than mess around with customer teams."

Toro Rosso and now-defunct Super Aguri were effectively customer teams, the former using a car designed by parent company Red Bull for both them and Red Bull Racing.

Super Aguri, who folded in April, used a version of Honda's 2007 car rather than building and designing their own as a constructor.

Formula One's regulations envisage teams running three cars each should the numbers drop below a certain threshold, although that could put severe financial pressure on some of the independents.

However, McLaren would have a ready-made partner in Force India, who last month agreed a deal to use McLaren engines and gearboxes.