RYANAIR'S 30 per cent stake in Aer Lingus damages competition on routes between Britain and Ireland and must be cut to five per cent, a regulator has ordered. The Competition Commission said the shareholding, which Ryanair has held for seven years, weakens its main competitor and could prevent Aer Lingus from combining with another airline in order to build scale. Ryanair boss Michael O'Leary said the company will appeal against the ruling and called the report "bizarre and manifestly wrong". Aer Lingus chairman Colm Barrington said the ruling showed that its main rival's shareholding went against the interests of 14 million passengers flying between Ireland and the UK.