Ryanair has said it will sell its Aer Lingus shares if another EU airline is able to acquire a 50.1% stake in the former semi-State company.
The airline has told Britain's Competition Commission it is willing to sell its 29% stake for the same price and terms as others should another company acquire a majority shareholding.
It said this offer "unconditionally removes" Ryanair’s ability to block any future takeover of Aer Lingus but a rival European airline.
Britain’s Competition Commission has been investigating Ryanair’s stake in Aer Lingus to see if it has allowed it to influence the commercial policy and strategy of the airline.
In provisional findings the commission said Ryanair could be ordered to sell its stake in the airline.
At the time it found that Ryanair's shareholding obstructs Aer Lingus's ability to merge or combine with another airline, which could help it to grow its operations.
Ryanair has continued to reject the commission's claims and said it had "produced no evidence whatsoever" to show that its stake had resulted in a lessening of competition.