Reports of secret Red Bull test emerge

Reports of a secret Red Bull test are starting to emerge in the wake of a

Bild newspaper report claiming that the reigning world champion team undertook testing indoors at the Austrian company AVL's rolling road facility in Graz.

The six-day test, involving Red Bull's troubled engine supplier Renault, reportedly occurred between the last pre-season track test in Bahrain and the start of the season in Australia.

Reports of the illegal test began to circulate after someone leaked correspondence to the FIA as well as the Mercedes, Ferrari and Sauber teams.

According to technical pundit Matt Somerfield Red Bull have denied being part of the test, which would suggest that Toro Rosso were involved instead.

But Red Bull test driver Antonio Felix da Costa had tweeted in early March that he was headed to Austria for a '5 day trip'.

"Spending the weekend in Graz, Austria," he added two days later. "Not by choice though!" (GMM)