Britain's Competition Appeal Tribunal has decided not to support Ryanair which wants to halt an investigation in the UK into the airline's 29% shareholding in Aer Lingus.
The Competition Commission wants to probe whether the Michael O'Leary-led airline should keep its stake in Aer Lingus.
Ryanair has argued there should not be an investigation on the basis that its full bid for Aer Lingus is to be examined by the European Commission.
Ryanair asked Britain's Competition Appeal Tribunal to take the case to the Court of Appeal.
But the Appeal Tribunal decided against that the appeal "would have no real prospect of success."
The development means the airline will have one week in which it can apply directly to the Court of Appeal itself.
In its judgement the Competition Appeal Tribunal said "Given the extensive work already done by Ryanair in formulating its grounds of appeal, we consider that it is appropriate to direct that Ryanair to renew its application for permission to the Court of Appeal (if so advised) within seven days."
