Sir Jackie Stewart has urged the world champion elect, Michael Schumacher, to retire from racing if he secures his record-breaking sixth title in the season-ending grand prix in Japan next weekend.

Schumacher, 34, needs just one point to be sure of this year's crown and put his name ahead of Fifties legend Juan Manuel Fangio in the table of all-time champions after winning the United States Grand Prix last Sunday.

But Stewart, who retired in 1973 after winning his third title at the same age as Schumacher, believes the German has seen the dominance of his Ferrari team eroded this year.

"He has to retire sometime," said Stewart. "There's nothing worse than a falling star. The new one soon arrives. Schumacher is currently the best but he must understand that nobody is irreplaceable and nobody is up on the pedestal for too long. And, for sure, he will be toppled like everybody else."

Schumacher has won the last three world titles but could still be pipped this year if Kimi Raikkonen can win in Japan and Schumacher finishes out of the points.

He has posted some poor results this season with seventh and eighth places in the German and Hungarian races respectively and he failed to finish the rain-hit Brazilian Grand Prix when he spun out in the deluge.

But his impeccably reliable Ferrari car has not let him down since the German Grand Prix in July 2001, 38 races ago, and after victories in the last two races the champagne is already on ice for a huge party in Suzuka.

Schumacher, before the race at Indianapolis, promised: "I am not thinking at all about retiring yet. I think it will be time for me to go when someone will beat me in a very clear and undisputed way.

"It will happen one day, I'm sure, and on that day I will have to say that it's over. But we have launched an incredible era for Ferrari and our goal now is to make it last as long as possible."

Schumacher has won 70 races in a 193-race career and will be equal seventh with the late Michele Alboreto in the list of grand prix starters when the current season comes to an end.

But Ferrari and Schumacher could be reaching the end of an era after their dominance faded this year, and Stewart believes Schumacher has shown his talent and should now get on with the rest of his life.

Stewart himself has gone on to play a major role in the development of the British motorsport industry through his involvement in the British Racing Drivers' Club and believes Schumacher could do the same in German motorsport.

The German is an ambassador for UNICEF, was recently made a special ambassador for the principality of San Marino and has already been offered a job for life at Ferrari when he retires.

And Stewart added: "Michael is very secure financially and you've got to move on in life and develop yourself."