BAR have confirmed that Takumo Sato will replace former world champion Jacques
Villeneuve as Jenson Button's team-mate next season.
Villeneuve has been with BAR since its inception in 1999, although his time with the team has been marked by a series of disappointments.
Sato, who made his Grand Prix debut at Jordan in 2002, has spent this season as BAR's official test driver.
The 2001 British Formula Three champion has the backing of engine
manufacturer Honda, who were keen to see a Japanese driver given his chance in F1.
David Richards, BAR team principal, said: "The team very much appreciates Jacques Villeneuve's commitment over the past five years.
"There comes a time in all relationships where you have to move on.
"Some people think it was a pre-determined decision taken a long time ago but I can contradict that completely.
"It came after long debate and the decision was taken internally.
"However, as his contract with the team has come to an end, we believe this is the appropriate time to refresh the driver line-up.
"We welcome Takuma as Jenson's team-mate for 2004. He has done an excellent job for us in testing this year and has confirmed our long-held belief that he has enormous potential.
"Takuma is widely regarded as a very fast driver and he has had a meteoric rise to Formula One. When he drove for Jordan in 2002 he had just four years' prior racing experience and during that first season we saw flashes of brilliance, which he underlined with an impressive performance in the Japanese Grand Prix last year.
"After a further year of testing with BAR in 2003, we firmly believe that he deserves the opportunity to translate his natural speed into consistent race performances.
"With Jenson moving into his fifth season in Formula One and his second with BAR, he will provide the counter-balance of experience alongside the fresh enthusiasm of Takuma.
"A young and hungry driver line-up is essential for us to move closer to achieving our Championship ambitions."
A delighted Takuma Sato commented: "Of course, I am extremely happy to be confirmed as race driver for BAR next year.
"This is what I have been working hard all year to achieve and now that the decision is made I am looking forward to proving myself again in the team next year.
"A year out of racing has been tough for me, but I am confident that the work we have done this year in testing has been extremely valuable in helping me and the team become a strong partnership.
"I have built good relationships with many people in the team this year and feel very positive that together we can be successful next season.
"Now, of course, I can't wait to start the build-up to the Australian Grand Prix in March."