DUBLIN • After spending years fighting the European Union (EU), Mr Michael O'Leary has turned into one of its biggest defenders, and he's even decorating his aircraft to prove it.
The Irish chief executive officer of Ryanair Holdings, Europe's largest airline, is trying to persuade the British to vote to stay in the EU in their June 23 referendum on its 43- year membership.
The company is donating money to the "Remain" campaign, and Mr O'Leary appeared in London on Monday alongside Chancellor of the Exchequer George Osborne to promote the case for staying in the EU.
"Let's get out and campaign," Mr O'Leary, 55, told a forum in Dublin organised by Bloomberg last Friday to discuss Brexit. "Businesses have got be very active. They tend to shy away from political involvement. We'll be criticised for doing it. For opponents who believe we shouldn't get involved, to hell with you."
Back in 2004, Mr O'Leary had denounced the European Commission as an "evil empire" as the European authorities consistently blocked Ryanair's efforts to buy Irish airline Aer Lingus Group. Yet if Britain is crucial to Ireland's export economy, it's even more so to Dublin-based Ryanair, which counts the UK as its single biggest market.
The company is spending €25,000 (S$39,000) on an advertising drive calling on Britons to stay in the 28-nation bloc. In addition to newspaper and online ads, the campaign will see the airline add vast pro-EU slogans to some of its aircraft, and e-mail customers to urge them to vote to stay.
"I despise much of the regulation that comes out of Europe that adds to consumer costs," Mr O'Leary said at the forum. "But there are sensible arguments for staying in, there are very few sensible arguments for leaving."
The Brexit camp hit back at Mr O'Leary, with Leave.eu on Monday running a video on its Twitter feed with the tagline "Guess someone didn't listen to their own advice".
It featured Mr O'Leary telling an audience in the Belgian capital in 2011 to "get the hell out of Brussels" and calling the European Commission headquarters the "Death Star".
So far, Mr O'Leary's contribution has included donating a "small amount of money" to the "Remain" campaign, and going up against "Leave" advocates on television debates such as the BBC's Question Time. He is by no means the only top business figure to publicly join the fray. In February, nearly 200 CEOs signed a letter calling for Britain to stay, including CEOs of retailer Marks & Spencer Group and mobile phone company Vodafone.
Among those lining up on the other side are former HSBC Holdings chief Michael Geoghegan and Mr Tim Martin, chairman of UK pub operator JD Wetherspoon.
Such opinions, including that of even US President Barack Obama, tend to show the alliances building on each side rather than have any overarching influence on the campaign, according to Mr Joe Twy- man, head of political and social research at polling company YouGov.
Mr Obama urged UK voters not to opt to leave the EU and warned relations with the US might be damaged.
"Interventions by individuals, even Obama, don't tend to matter to very many people for very long," Mr Twyman said. "Nobody will go into the polling booth basing their decision just on what Michael O'Leary said."
And Mr O'Leary's suggested tactic for the rest of the campaign? "I'd want to terrify the life out of everybody that there's a real danger the lunatics on the "Leave" side are going to win," he said. "So get out and vote."