Flogging Molly were performing at a festival in Washington DC last year when a man brandishing a Donald Trump t-shirt stood up and walked through the crowd. Surveying the scene from stage, singer Dave King didn’t know what to do. A few years ago he would in all likelihood have confronted the interloper, whom he presumed to be a Trump supporter. Now, he wasn’t so sure. Say the wrong thing and the situation might turn ugly.

"There was a time I would have poked fun at that," he recalls. "But for the first time in my career I actually took a step back. All I said was, ‘don’t laugh – this could be your neighbour next year’. I was actually terrified. I would have called that person out big time not long ago. It struck me that, if I did so at that moment, things could have ended up really badly. We’re living now in a world of fear."

King appreciates better than most Irish people how Trump came to be elected – and the threat he poses to America’s founding values. The frontman’s principal residence is in Wexford but he and his American wife, Bridget Regan, also maintain a home in Detroit. He understands the poverty and hopelessness that swept the Orange One into the Oval Office.

"You can see how someone is not happy with the system of government – how they would vote for someone they would not normally vote for. But it is pretty bloody scary. When the Brexit vote passed, I kind of knew Trump was getting in."

With Trump elected President, the Brexit fallout ongoing and North Korea threatening to nuke us to the Stone Age, these are self-evidently scary times. So when Flogging Molly toured the Continent recently journalists, some of them quite angry, confronted King over the band’s new album – specifically its title, Life Is Good. He sighs. Some things just don’t translate.

"I got a lot of stick from critics there. The point of the album of course is that life isn’t good. It sucks."

There’s another, more personal, story behind the choice of name. King’s mother died at St Vincent’s hospital in Dublin in 2016. "She said to me and Bridget – "do us a favour and enjoy your life…because I did". So that explains the album title. It has nothing to do with the fact life is good."

Flogging Molly, who bring their latest tour to the Olympia in Dublin this Sunday, are a difficult band to pin-down. Their style has been described as "Celtic Punk" – arguably a clumsy catch-all for their fusion of traditional rhythms and pedal-to-the-floor guitars.

King’s roots are in heavy rock. He cut his teeth with Fastway, a head-banging outfit put together in 1983 by "Fast" Eddie Clarke, ex of Motörhead , and UFO’s Pete Way. King, then an unknown from inner Dublin, was their surprise choice as vocalist.

As that project fell apart, he was approached by Epic Records with the suggestion that he team up with guitarist Jeff Beck. Having had enough of being a side-kick King demurred and Flogging Molly were born.

"Everyday is a new day for band like this," says the now 55 year-old. "We headline punk festivals, folk festivals, metal festivals. We’ve played with Motörhead and we’ve played with The Chieftains. It runs the gamut."

He’s acquired more than a few famous admirers along the way. When George W Bush was US President, King persuaded Will Ferrell to deliver his famed impersonation of the then Commander in Chief for a video played before Flogging Molly went on stage every night. He’s not sure the same gag would work with Donald Trump. People on both sides just feel too strongly.

"You have all the late night talk show hosts taking the piss out of Donald Trump. You can’t do that as a live performer, when you’re on the frontlines. You are not in front of a camera in a studio. You are out there looking people in the eye. That makes a difference."

Flogging Molly play The Olympia Dublin this Sunday. The album Life Is Good is out now.