The UK Competition Commission has been given the go ahead to investigate Ryanair’s shareholding in Aer Lingus.
It has won the right to evaluate whether Ryanair’s 29.8% stake gives it undue influence over its rival.
Ryanair had tried to fight against an investigation, arguing that it would undermined a separate probe by the European Commission.
Aer Lingus welcomed the decision and said it was "a key milestone on the path toward Ryanair being required to divest its shareholding in Aer Lingus".
But Ryanair said it would now ask the UK’s supreme court to hear another appeal.
