F1 commercial rights-holder Bernie Ecclestone has admitted his fears that two of the 2010 newcomers are unlikely to make the starting grid for the curtain-raising Bahrain Grand Prix in mid-March.

USF1, Campos Meta 1, Virgin Racing (formerly Manor Grand Prix) and Lotus F1 are all set to swell the field next year, but there has been a considerable degree of scepticism about just how well-prepared they are - and whether all four will even make it to Sakhir.

USF1 was the first of the four to pay the required $440,000 entry fee, whilst Campos has signed up Bruno Senna - former GP2 Series runner-up and nephew of the late, great three-time F1 World Champion Ayrton Senna - and claimed the honours in terms of being the first to get its Dallara-designed chassis past two of governing body the FIA's mandatory crash tests.

Lotus and Virgin, by contrast, have already both firmed up their entire driver line-ups, but with concerns over the financial resources available to Spanish outfit Campos and persistent speculation that USF1 is going nowhere fast [see video - click here], Formula One Management (FOM) chief executive Ecclestone has revealed that he believes only 24 cars will make up the pack in Bahrain - with USF1 and Campos absent, and one more newcomer joining to fill the void. Initially unsuccessful Serbian applicant Stefan Grand Prix looks to be the most likely candidate in such an eventuality.

"I think the people we expected to perform will, and those that we thought wouldn't, won't," the 79-year-old billionaire told British newspaper The Times.

Should Campos indeed fail to make the grade, it would represent a particular blow for Senna, just twelve months on from being within touching distance of top flight graduation with 2009 F1 World Champions Brawn GP, only to be passed over at the eleventh hour in favour of more experienced compatriot Rubens Barrichello, who went on to finish third in the drivers' standings this year.