The move, which Ryanair slammed as “unnecessary” and “damaging”, is part of an OFT probe into whether Ryanair’s 30 per cent holding in the carrier gives it undue influence and hampers competition.
Ryanair maintains that the OFT has run out of time to examine the failed merger, which fell through five years ago, and in any case has no jurisdiction over a deal between two Irish companies.
But last month the Competition Appeal Tribunal said the OFT could still pass the case onto the Competition commission for further investigation.
“[I]t appears that the OFT now intends to second guess and become involved in mergers up to nine years after the transaction, only once all EU appeals have been completed,” said Ryanair in a statement.
Ryanair, Europe’s biggest low-cost carrier, first acquired a stake in Aer Lingus in 2006 and mounted a public bid for its entire shareholding late that year, but the European Commission investigated the bid and decided to prohibit it in June 2007.