Willi Weber, who manages the Schumacher brothers, has told a German newspaper that seven-time champion Michael, might retire at the end of the 2008 season.

"I can't say now that it is with any certainty but I think that the end of 2008 is probably the end for him," he told Stuttgarter Nachrichten. "But I could be wrong."

Schumacher's current contract with Ferrari lasts until the end of the 2006, and the German racer has always said that he will see out his career with the Italian team, and has no intention of moving to another. In a year in which F1 has crowned its youngest ever champion, Schumacher, at 36, is the oldest on the grid.

For several years there has been speculation as to when the German will hang up his helmet, and many thought that having lost his 'crown', the end of the current season might be the best time. However, it is clear that the Ferrari star has lost none of his verve for racing, far from it.

On rumours that Schumacher could move to Ferrari, Weber was adamant. "Right now I can rule out this link. It doesn't make any sense. First of all, Michael feels totally comfortable at Ferrari. And secondly, Schumacher wouldn't be better to market at Mercedes than Ferrari.

"Mercedes symbolises luxury cars and Ferrari sports cars," he added, "and that image extends to every corner of the world. At Ferrari, everyone thinks about races, motor sport, Formula One. For a driver's image that's much better."