THE decision by the British Court of Appeal to allow the Office of Fair Trading (OFT) to investigate whether Ryanair should be forced to sell its stake in Aer Lingus is a blow to Michael O'Leary.
The ruling could remove an obstacle that has put off potential bidders for the former national carrier.
The prospect of having your main rival as a militant, vocal shareholder wold have been a stumbling block for many airlines, even at a time of widespread consolidation in the industry.
Ryanair immediately appealed yesterday's ruling to the Supreme Court.
That step more or less guarantees that the legal challenges will carry on into a third year, but at this point UK authorities have signed off three times on the investigation, which will first try to establish if the OFT even has jurisdiction over Ryanair and Aer Lingus.
In a statement after the ruling was made public, Aer Lingus chief executive Christoph Mueller described Ryanair's stake in the former national carrier as "unacceptable" and an "intolerable situation that cannot be allowed to continue".
Six years after Mr O'Leary started building an Aer Lingus stake, Mr Mueller may be on the verge of getting his way.