Frank Williams has expressed his unease with Bernie Ecclestone's plans to expand the Grand Prix calendar to as many as 20 races, fearing such a move would lead to problems on and off the race track.

Ecclestone has made no secret of his desire to increase the number of races on the F1 calendar, for such a move would increase the revenue from race promoters and TV broadcasters. However, though such a move is favoured by some within the paddock, most notably Flavio Briatore, others have made no secret of their unease at the prospect.

Following Ecclestone's recent comments to L'Equipe, when the Englishman said that the calendar must be expanded to 20 races by 2009, Frank Williams has once again voiced his concern.

The Englishman claims that such a schedule would have a negative impact on his employees, a view previously expressed by Ron Dennis.

"We have all lost people who have not been able to withstand the enormous pressure and stresses of these calendars," Williams told Motorsport Aktuell.

He is also worried that an increase in the number of races would lead to less testing, which in turn could to problems with safety.

"Just as new aircraft need safety checks, we also need to test," said the Englishman. "It is inescapable that more test restrictions will lead to more accidents."