Formula One has many warning flags but none to signal the end of an era.

It would have come in useful in a year of significant change coloured strongly by Renault's 24-year-old Spaniard Fernando Alonso [Images], now the sport's youngest champion, and McLaren's Kimi Raikkonen [Images].

The longest season in the sport's history, with the championship stretched to 19 races with the new and welcome addition of Turkey, has witnessed the passing of a baton from one generation to another.

Even if Michael Schumacher [Images] refuses to admit it, the Red Baron who has dominated the scene with Ferrari [Images] since the end of the 20th century now looks like a man whose greatest achievements are behind him.

The German, now 36 and the oldest driver on the track as well as the most successful with seven titles and 84 wins, has been dethroned with surprising ease after five continuous years as world champion.

Formula One's longest ruler was mathematically out of contention after his team's home Italian Grand Prix in September but he had ceased to be king of the road long before.

"I have been champion for a long time and I am more surprised by how long it has been. I always knew it would end one day," said Schumacher.

Ferrari, holders of the constructors' title for six successive years, cannot now fare better or worse than third place overall -- whatever happens in Sunday's season-ending Chinese Grand Prix.

YOUNGEST CHAMPION

Alonso, winning the title in Brazil [Images] with two races to spare, and 'Iceman' Raikkonen have been more than a match for Schumacher.

They have provided the defining moments of the season, with Alonso holding off the Ferrari ace for lap after lap to win at Imola in April and both overtaking the powerless German at Suzuka in Japan [Images].

Theirs has been a duel that holds out the prospect of a return to the sort of riveting Ayrton Senna-Alain Prost rivalry that once lit up the sport before Schumacher and Ferrari's domination stifled the opposition.

After a season overrun by Ferrari, with 15 wins in 18 races, this year's season-opener in Australia threw up an immediate surprise with rain shaking up the starting grid and Renault's Giancarlo Fisichella winning.

Remarkably, Schumacher failed to finish.

The sense of a shift of power grew in the following Grands Prix, with Ferrari looking increasingly desperate and out of sorts while Renault won the next three races.

Only in May, in Alonso's home Spanish Grand Prix, did Raikkonen finally open McLaren's account -- after the team's prospects were blunted by the absence of Colombian Juan Pablo Montoya [Images] due to a bizarre accident while playing tennis.

By then, however, Alonso had started to build up the crucial lead, and shown the reliability, that would stand him in championship-winning stead.

Raikkonen has won more Grands Prix, led for a greater distance and collected more fastest laps than anyone else this year but both he and McLaren could still end the year empty-handed.

In China, he could even become the first driver to win eight races in a year without winning the title.

HOLLOW SUCCESS

While Renault and McLaren confirmed their pre-season potential, Ferrari, BAR and Williams were the big disappointments.

The Italian team have just one win to their credit, the hollow success of Indianapolis when only the six Bridgestone-equipped cars raced after the Michelin teams withdrew for tyre safety reasons.

Some saw the shame of that race, with angry fans hurling cans and bottles at the track, as the end of Formula One's American adventure.

It was not, with the race confirmed again for next season after Michelin compensated fans and agreed to buy thousands of tickets for 2006, but it did represent the lowest point the glamour sport has sunk to in years.

Formula One, buffeted by an increasingly bitter power struggle between carmakers and the governing body, was still recovering from the controversy caused by BAR's two-race ban for weight and fuel irregularities.

That situation left BAR, runners-up the previous year, without a point after nine races and facing the loss of leading driver Jenson Button [Images] -- who this weekend starts his 100th race -- to Williams.

The situation was resolved only when Button paid millions to buy himself out of his contract and agreed a new long-term deal with BAR, who will become 100 percent Honda-owned in 2006.

They were one of four teams involved in the biggest changing of the guard in the sport's recent history, with the Minardi, Jordan, BAR and Sauber names all set to disappear after takeovers.

Red Bull's rookie team, their parent company a newcomer this year after buying Jaguar, join Midland, Honda and BMW [Images] in preparing for 2006 debuts after taking over the smallest 'independents' on the grid.

The wail of the V10 engine will also vanish after Shanghai, its sound to be replaced by the new era of 2.4 litre V8 units.

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