Microsoft's legal challenge against last year's European Commission antitrust ruling will not be decided by the judge initially responsible for the case, and has now been moved to the European Court of First Instance's grand chamber.

This means the US software group's appeal will be heard by a panel of 13 judges under the guidance of Bo Vesterdorf, the Court's president. The grand chamber of the European Union's second-highest court has only come together once before, to rule on the relationship between international trade law and European Union legislation.