The FIA has defended its decision to appoint a member of its Court of Appeal to provide an “independent” opinion on whether its president engaged in sado-masochistic sex with prostitutes that had “Nazi-style” connotations.

The FIA issued a short statement on Monday indicating that senior officers had decided to appoint the leading barrister, Anthony Scrivener, QC, to give his opinion on allegations by the News of the World that Max Mosley engaged in Nazi role play during a five-hour orgy with prostitutes in March. Scrivener, who has been a member of the FIA's International Court of Appeal since 2006, will produce a report that will be made available to the 222 voting members of the sport's governing body at the extraordinary general assembly in Paris on June 3, when they will decide Mosley's fate in a secret ballot.

The FIA president's critics in motor sport greeted the announcement of Scrivener's appointment and narrow remit with scepticism, questioning his independence and expressing alarm at the way the ground was being shifted to a debate within the FIA about the alleged Nazi element and away from the wider issue of whether or not Mosley is a fit and proper person to lead the organisation.

One senior Formula One source said that he was shocked but not surprised to learn of Scrivener's appointment. “I thought, 'Here we go again,'” the source said. “Everything is an inside job under Max's rule.” Another gave warning of serious commercial consequences if Mosley is not effectively dismissed next month. “I think there is a danger that some of the sponsors will take matters into their own hands if Mosley survives,” he said.

Richard Woods, Mosley's spokesman at the FIA, rejected criticism of Scrivener, who is thought likely to approach either the News of the World to obtain a copy of its film of the orgy or ask Mosley for his copy. Woods said that Scrivener had knowledge of motor sport, had “very direct experience of issues involved with the FIA” and is a lawyer of “impeccable reputation and credentials”. He added that the appointment of Scrivener had not been Mosley's idea and that senior officers of the FIA had been discussing the need for an independent report.

The number of Formula One teams was reduced to ten yesterday with the announcement by Super Aguri that they are going out of business after failing to find sponsor support, leaving Anthony Davidson, the British driver, without a team. Super Aguri have been supported by Honda over the past year, but the manufacturer's money and patience have run out. Honda has given £35million to the small Japanese team over the past 12 months, including £100,000 to enable them to compete in the Spanish Grand Prix ten days ago.