The Toyota team have secured a major coup by luring top Formula One designer Mike Gascoyne away from Renault.
Gascoyne has masterminded Renault's return to competitiveness in F1 and Toyota have hired him to do the same job for them in the next four years.
He will join Toyota on 1 December so will have little impact on the initial design of their next F1 car.
It is a blow to Renault, who struggled in their previous guise as Benetton before Gascoyne joined in 2000.
Renault will promote deputy technical director Bob Bell as Gascoyne's replacement.
"I am looking forward to my exciting new role at Toyota with great enthusiasm and, together, we will relish the long-term challenge of developing Toyota into a world championship-winning team," Gascoyne said.
Renault boss Flavio Briatore paid tribute to the contribution of Gascoyne but insisted that Bell's promotion would benefit the team.
"The entire technical team has done an outstanding job developing our car over the past two years and we have made impressive progress," he said.
"Our programme has been built up carefully, putting the right people in place and I have every confidence that Bob's technical experience and managerial skills will be a major asset for the future.
"We are looking forward to 2004 and beyond. Things are in place for us to step up to even bigger challenges and fight consistently with the other top teams."
Gascoyne is reputed to have been lured to Toyota by a huge salary of over £4m in a move predicted by the BBC Sport website in June.
That would make him possibly the highest-paid designer in F1, with only McLaren technical director Adrian Newey reputedly earning anywhere near the same amount.
Toyota have decided to pay that money because of the reputation Gascoyne has earned in the last few years.
Toyota have made no secret of their ambition to win the title since they entered F1 for the first time in 2002.
And Gascoyne has successfully turned both Jordan and Renault from troubled teams with potential into race-winners.
The impact he had on Jordan has come to be viewed as even more impressive in light of the team's decline since his departure.
Renault, who Gascoyne joined in 2000 after leaving Jordan, are reputed to have the best chassis in F1 this season.
Its qualities have been masked to some degree by a down-on-power engine, but the package was still good enough to take Fernando Alonso to victory in Hungary.