Red Bull buys back STR stake.

Red Bull has announced that it is to buy back the 50 per cent stake in the Toro Rosso Formula One team that it sold to Gerhard Berger back in 2006.

Berger went into partnership with Red Bull chief - and long-time friend - Dietrich Mateshitz ahead of Toro Rosso's first season in F1 after Red Bull purchased the Minardi team from Paul Stoddart.

The partnership saw Red Bull provide the financial and technical backing and Berger admitted that such a situation wasn't feasible in the long-term.

"A 100 per cent financing of a joint project by one partner can only make sense, to my mind, at an initial stage," he said. "This stage is over now. That's why Red Bull will take over the shares again."

Under the joint partnership, Toro Rosso emerged as the surprise package of the 2008 season, with Sebastian Vettel taking his - and the teams - maiden win at Monza.

Such was the performance of the team during the season that it ended the year sixth in the constructors' championship - ahead of the sister Red Bull team by ten points - but it will now return wholly to Red Bull ownership ahead of 2009.

"I'm very grateful to Gerhard for his enormous input," Mateschitz said. "Together we have made Toro Rosso a team which, from 2008 onwards, will regularly qualify for the top ten and collect championship points."

Toro Rosso is currently the only team on the Formula One grid without any drivers signed for the 2009 campaign, with Vettel having moved on to the 'senior' Red Bull team.

Sebastien Bourdais, Sebastien Buemi and Takuma Sato all tested in Barcelona last week, while Rubens Barrichello and Bruno Senna are also reported targets - dependent on the line-up announced at Honda.