Ryanair has lost a bid to stop Aer Rianta suing it over claims that Ryanair had in 2001 "unjustly enriched" itself by overstating to passengers the level of airport charges and not passing on the full amount to Aer Rianta.
The complaint about charges is part of an action being taken by Aer Rianta in which the airport company alleges Ryanair issued a press release and falsely published on its website in 2001 that Aer Rianta was levying a service charge of £9.50 in 2001 when the approved rate was £7.23.
Aer Rianta is suing Ryanair for defamation and seeking damages.
As part of its action, Aer Rianta alleges Ryanair unjustly enriched itself by retaining for its own benefit the so-called "passenger service charge" or tax levied on its passengers where, for any reason, the passenger failed to fly as scheduled. The airport company stated that Ryanair must account to it for these monies.
Ryanair lost a High Court application last year to have Aer Rianta's claim of unjust enrichment struck out. Ryanair claimed that Aer Rianta had not pleaded that the alleged unjust enrichment was at Aer Rianta's expense.
Yesterday, the Supreme Court upheld the High Court decision.
Delivering the court's judgment, Ms Justice Denham said the jurisdiction under the rules of court to strike out pleadings was one which a court was slow to exercise. The rule spoke of "pleadings" and did not relate to part of pleadings. The court had jurisdiction to strike out an entire statement of claim but not portion of it.
To develop what Aer Rianta had referred to as a "blue pencil" jurisdiction would have inappropriate consequences, the judge said. It would have the potential of initiating a whole new jurisdiction of applications where parties sought to strike out parts of statements of claim or defences. This could herald a whole new list in the High Court where parties would be fighting on the pleadings and this would involve further costs and be time consuming.
The court, which also consisted of Mr Justice Hardiman and Mr Justice McCracken, struck out Ryanair's appeal.