Dropkick Murphys are a rare breed. Boston’s pride, the Celtic punk rockers are kicking off their third decade as a band, with their famous flame of passion showing no sign of dwindling to a flicker. It’s burning more fiercely than ever, frontman Al Barr and guitarist Tim Brennan tell me, as we slump into leather sofas surrounded by guitars in London’s Gibson Studios.

It’s impossible to separate this six-piece from their fans, so much so that new song “Blood” from their upcoming ninth album 11 Short Stories of Pain and Glory is a homage to the mutual respect and dedication they share. Unlike many contemporary bands, the Dropkicks do not rely on radio airplay to get their music heard. They have shifted over four million albums globally, fan favourite “Rose Tattoo” has racked up over 24 million hits on YouTube, and they are regularly drowned out on tour by crowds singing along to songs that have never been officially released. They are fully aware how lucky they are, which is why the group set up their own charitable foundation, The Claddagh Fund, in 2009, to help support recovering addicts, vulnerable children and veterans. The band has always been deeply ingrained with local neighbourhood politics, often highlighting causes by wearing campaign T-shirts on stage to selling their own to raise money for others in need. “Doing these things is a way to keep the ethos that has always embodied Dropkick Murphys,” says Barr. “It’s a great way for us to give back and it’s been inspiring to see the outpouring of love and generosity from our fans. It feels good to help.”

For the first time since forming in 1996, the Dropkicks decided to record the album outside Boston. They packed their bags and headed to a remote studio near El Paso in Texas for “pure isolation” without the distractions of everyday family life. “The idea was to be surrounded by nothing and focus 100 per cent on completing the album,” says Brennan. “It’s human nature to resist being taken out of your comfort zone but it turned out to be a wonderful experience.” While there, the band heard that notorious drug lord Joaquin ‘El Chapo’ Guzman had been transferred to a Mexican prison close to the US border. “We thought, ‘Oh man, that guy is right over there!’” laughs Barr, adding that there was no mobile phone signal bar in the area. They were completely cut off, with only themselves and their instruments for company.

The new record is a powerfully gritty soundtrack to tragedy and triumph but one song stands out as one of their most emotional to date. The sombre, folky “4-15-13” is a tribute to those affected by the Boston Marathon bombings, many of whom the Dropkicks got to know personally after visiting their hospital rooms in the aftermath. The band decided that not writing a song about an atrocity that so profoundly destroyed their hometown’s innocence would be the coward’s way out, but they had to get it right. “You can’t have your own interpretation of that day,” says Barr. “You’re not writing about something that happened a hundred years ago. There’s a chance that somebody who is mentally fucked for the rest of their life because of it is going to hear these songs. So we had to be mindful and cautious of how we presented it.” The band were on tour at the time of the terrorist attack and felt guilty for not being at home. “It left us feeling extra helpless and we wanted to be with our families,” Brennan explains. “It was a poignant, scary time for us and for the city.”

Nevertheless, the Dropkicks remain committed to their fans, playing a small club in Santa Cruz, California, just hours after hearing the news. Barr still remembers the cheers and applause of gratitude and support. “People expected us to cancel as it was right after it happened,” he says. “Ken’s wife and kids were three blocks away, but we realised that if we went home, we wouldn’t be able to help anybody. We aren’t doctors, but we can play music and deliver a message of hope through our songs.” Not ones to miss a fundraising opportunity, the band put ‘For Boston’ shirts on sale outside their gigs. In just four days, more than 400,000 had been sold, with the proceeds going straight to help the victims. “It was our fans who did that, not us. We were just a conduit. It was an amazing and beautiful thing.”

Not all high profile artists are so selfless, but Brennan is optimistic that using power for good is becoming a more important part of the industry. “Bands with their feet on the ground are leading the charge in terms of using their popularity to bring attention to issues that aren’t being talked about enough,” he says, before suggesting that “super uber bands” making millions of dollars should start upping their game. “Some people have so much money while others have nothing and it boggles my mind that there isn’t a sense of responsibility to try and make a difference after attaining a certain level of success.” Father-of-three Barr has been profoundly affected by the change of perspective brought on by parenthood. “I will never forget the feeling when I held my first son Strummer in my arms. I felt something in my heart and soul that I’d never felt before and I understood my parents for the first time,” he says, adding that he cut the umbilical chords for all his children. “With your teeth right?” jokes Brennan, in a bid to bring some rock’n’roll back into the conversation.

Starting families and developing an awareness of social issues has had a strong impact on the band’s songwriting, with much of their latest music directly addressing the causes closest to them. Tracks such as “Rebels With a Cause” and “Paying My Way” see the band express their rage and despair at the rampant opioid epidemic ravaging New England, which hit home when Barr’s brother-in-law died of a heroin overdose two years ago. “My sister found him in his car dead and she had no idea that he was even doing it,” he says. “The syringe was still in his arm and it wasn’t even nearly empty. He’d injected the tiniest bit but it had been cut with fentanyl and it killed him immediately.” Synthetic drug fentanyl is fifty times stronger than heroin and found in dozens of pills, including mislabelled counterfeits found at Prince’s home after he died from an accidental overdose earlier this year. The band’s bass player, Ken Casey, has been to more than fifty funerals in the last four years and also recently lost a family member to an overdose. The moving cover of “You’ll Never Walk Alone” on the album came about after he heard it on the radio while leaving yet another wake and was struck by how pertinently the song related to the struggle. The problem is so rife and hospital resources so stretched that clinics have been set up for addicts to inject heroin safely, while others become addicted to methadone after initially using it in a bid to wean themselves off heroin. “The fucking pharmaceutical companies are raking in the profits on this stuff and they don’t care about the bodies they’re stepping over to cash their cheques,” says Barr. “There’s 1.3 million people in New Hampshire, which is not a lot, but we’re number one in the US for heroin overdoses. It’s insane and there’s no end in sight.”

The band were deeply affected by the recent presidential election, with Barr blaming “the greed of the Clintons” for Donald Trump’s controversial victory. “The election was lost when it was stolen from Bernie Sanders. Six and a half million Democrats voted Republican and they were the same people who voted for Barack Obama, so it’s too easy just to say they’re racist,” he says. “They’re not voting for a black guy twice if they’re racist. It was a fuck you to the Clintons.” Similarly disenchanted fans will be able to chant the new Dropkicks songs loudly and proudly on their next tour as the group are determined not to let maddening political events bring them down. In just forty minutes, 11 Short Stories of Pain and Glory sums up life – the good, the bad, the happy and the sad – and brims with their trademark defiant, Celtic punk attitude. “We truly put our heart and soul into every record we’ve ever made,” they say. “We wouldn’t let it go down any other way. We’ll break up before that happens.”