Sir Jackie Stewart has warned Formula 1 bosses to respect the sport's traditions by preserving European races, which are under threat of disappearing.

F1 will be without a German Grand Prix on the calendar for the first time since 1960 after officials at Hockenheim could not afford to stage the event.

However, Stewart has suggested that the sport must do more to keep "essential" races going.

He told The AP: "That sounds like me being a purist, but you have to respect history.

"They should always be on the calendar — it's terrific we have a United States Grand Prix, a Brazilian Grand Prix, one in Bahrain, and that we are going to new countries. But you still have to respect your heritage."

The Italian Grand Prix is also thought to be under threat, although recent reports suggest that the Lombardy regional government has agreed a rescue grant to safeguard the future of the famous Monza autodrome.