Niki Lauda has suggested that Formula 1 drivers should 'double up' again as they used to back in his day - arguing grand prix winners like Lewis Hamilton and Sebastian Vettel could also be put to use in the DTM to boost the popularity of the pan-European touring car series.

Back in 1979 and 1980, the BMW M1 Procar Championship saw F1 stars not only competing in the top flight, but also in the one-make series featuring identically-modified BMW M1 sportscars - on the same weekend.

Lauda himself triumphed in the inaugural Procar campaign as the championship supported a number of European rounds on the grand prix schedule, with fellow triple F1 World Champion Nelson Piquet emerging victorious the following year. Other big-name drivers to win races were Carlos Reutemann, Jacques Laffite and the late Didier Pironi and Elio de Angelis.

Lauda believes that by doubling up in the DTM, drivers would be saving their employers money whilst helping the leading tin-top series to effectively overcome the debilitating effects of the credit crunch. There are no clashes between the 2009 F1 and DTM calendars, and the new ban on in-season testing in the top flight has provided the drivers with far more free time, the Austrian contends.

"In these difficult times Mercedes could use Hamilton [for its DTM team]," the 59-year-old racer-turned commentator told German-language news magazine Focus, "and Vettel could be put to use by Red Bull Audi."

Lauda added that he is not, however, in favour of proposals to cap or limit F1 drivers' salaries - one of FIA President Max Mosley's suggestions in the name of cost-cutting.

"Utter nonsense," the 1975, 1977 and 1984 World Champion retorted. "It is a free market."