BMW thanks Kubica for his efforts

Kubica's team switch had been widely predicted in recent weeks, with Renault immediately regarded as the favourite to sign him once BMW announced that it was pulling out of the sport.

BMW team boss Mario Theissen said Kubica's contribution to the company's history would always be valued. He took the works BMW squad's first Formula 1 pole position and victory in 2008, when he also fought for the world championship with the team.

"Robert played an important role for us - and certainly we did the same for him," said Theissen.

"He joined us in 2006 as a test driver with no Formula 1 experience, and then we promoted him to be one of our team's drivers during that season.

"He never let us down and, with our first pole position in 2008 in Bahrain and first victory the same year in Canada, he set milestones in the history of our team. We are grateful for his strong and constant performances and wish him all the best for his future."

Kubica was promoted from BMW's third driver role to a race seat in place of Jacques Villeneuve in the middle of the 2006 season, and took third for the team at Monza in only his third race.

There were tensions between Kubica and the team last year when the Pole became frustrated that BMW was diverting its resources towards 2009 preparations rather than putting everything into a 2008 title bid. But he said he would always be indebted to BMW for giving him his F1 break.

"I'm very thankful to those responsible in the BMW Sauber F1 Team for giving me the chance to get a Formula 1 cockpit," said Kubica.

"I think I justified the belief in me by delivering good results. In 2008 I managed to get the first pole position in Bahrain and the first win in Canada. Both will remain unforgettable moments for me.

"For 2010 I will have a new challenge. I wish everybody I worked with at the BMW Sauber F1 Team all the best for the future. I'm sure in the future our paths will cross in Formula 1."

The BMW Sauber team's future is currently unclear as although it has been bought by investment group Qadbak, it lost its guaranteed place on the 2010 F1 grid when the parent company withdrew - and that slot then went to the revived Lotus team. Its hopes now depend on another team dropping out or the FIA succeeding in expanding the entry to 28 cars.