Thursday 11 March at 18:01 : Mar.11 (GMM) Yet another world champion has stepped into the mix for this weekend's sensational 2010 season opener in Bahrain.

Active drivers' title winners Michael Schumacher, Jenson Button, Lewis Hamilton and Fernando Alonso posed for photographers in the FIA press conference.

Shortly afterwards, it emerged that quadruple world champion Alain Prost will act as a steward throughout the race weekend.

The governing FIA said late last year that permanent stewards will in 2010 "sit with experienced former F1 drivers" to "reach decisions very efficiently".

55-year-old Frenchman Prost, the arch-nemesis of 2010 rookie Bruno Senna's late uncle Ayrton, won four titles and 51 wins in the 80s and 90s, and headed his eponymous team until 2001.

Meanwhile, the World Motor Sport Council met in Bahrain on Thursday, and vowed to take "the most appropriate action" in the wake of USF1's failure to appear for the first race of the season.