Think of a UK punk band on their first US tour and you might imagine a boozing, drug-snorting ragtag cliche. If I’d encountered Bristol band IDLES a couple of years ago, my time with them may well have resembled that. Back then, I may have seen coke-crusted noses hovering over pints sucked down into the early hours rather than frolicked in a park and eaten ice cream with the five-piece, as transpired over a recent weekend in New York. Chances are, really, that IDLES wouldn’t have been able to keep it together while saying yes to every line and drink on the road. “If I’d have been doing this in my twenties, I’d be dead,” 33-year-old frontman Joe Talbot says of life on tour, as he and his bandmates unload their gear at Brooklyn venue Ceremony. “I was nearly dead just being a barman.”

Now, he’s sober and filling the air with the artificial smell of the dessert-flavoured nicotine that flows from his e-cigarette. IDLES are on the opening weekend of a two-week North American tour, and I’ve tagged along for the first couple of days. Though the five-piece got together in 2012, the journey to releasing critically acclaimed debut album Brutalism last year was mired in grief and pain, which was then self-medicated with drugs and alcohol. But what you need to know for now is that IDLES sound like Fugazi by way of political – and often humorous – UK groups like Sleaford Mods and Fat White Family . In the time I spend with them, going from sweaty venues to killing time before shows on New York’s streets, I come to see how much of a unit they are, and how their angry-sounding music is rooted in a cathartic honesty.

So: to the gig they’ve unloaded for. A giant disco ball spins in Ceremony as the room fills to sold-out capacity with a mix of hardcore sing-every-word fans and younger first-timers. Returning from their apartment, the band take to the cramped stage. Talbot, last to arrive, walks in the door, straight through the crowd and onto the stage before the band overload the venue with their blend of melodic post-punk and post-hardcore. Along with Adam Devonshire on bass, guitarists Mark Bowen and Lee Kiernan and drummer Jon Beavis, Talbot howls through a set filled with hit-you-over-the-head lyrics about depression, grief, toxic masculinity, shit towns and Tories. He introduces anti-privatisation track “ Divide & Conquer ” as one about the UK’s National Health Service, “where if people are poor and they get ill, they get looked after. Not a bad idea, is it?” His eyes are wired, teeth gritted, and face strained as he faces the crowd.

“We were becoming frustrated with each other,” he remembers. “I'm really difficult to be around a lot of the time. I'm not always a nice person. I was drinking and doing drugs a lot and because of that I was hungover and on a comedown a lot. I'm then ten times worse.” We’re having lunch at Katz’s Deli, a Jewish New York institution, where a signed picture of Ben Stiller hangs on the wall above Talbot’s head as he recounts this. He says he’s now sober but then, “I was looking after my mum five or six days a week in Newport and then coming back to Bristol and DJing and doing band practise. I really resented my situation, knowing that all my mates were living normal lives and I’m watching my mum die slowly. She was such a happy person and the joy was starting to leave her. I couldn't hide how scared I was so I was drinking more and doing more drugs and it became a spiral of just trying to numb any reality.”

Talbot doesn’t just express a love for the NHS to antagonise American audiences who have to pay thousands for healthcare. When he sings about how “a loved one perished at the hands of the barren-hearted right” he’s referring to his late, disabled mother. “My mum’s life was shortened due to NHS cuts, that’s a fact,” he tells me over coffee the next morning, his voice already croaky despite it being the beginning of this two-week run. He tells me he was her carer before she died during the making of Brutalism – it was, needless to say, an unbearably tough time, for him and the band more broadly.

“Right then,” Talbot spits back, seeming to take the shouted comment as an anti-NHS heckle. “Well this one is for the person who hates poor people” – and soon the song’s sparse but heavy drums build up to a Cramps-like release. It feels like the sonic equivalent of attempting to drown Theresa May in guitars, and sends the crowd into a sweat-drenched tizzy, drinks flying from their glasses.

After lunch, Talbot, guitarist Bowen and I try to find somewhere quiet in the city’s midday Saturday buzz and decide on a plush hotel lobby. We wind up talking about how Brutalism became like a moment for them all to hit reset. “I think what happened was that we started making music purely for ourselves and not being worried that it was going to be a successful album,” Bowen says, “and it all then just gushed out.” Talbot adds: “We stopped caring. We gave up on the industry, massively. We did not give a shit about agents and labels; at that point our skin was so thick that we couldn't feel anything. We weren't sending out our music anymore, it was just like ‘fuck it, let's make an album.’”

But he and the band held on. They’d taken a while to find their sound on EPs Welcome , from 2012, and Meat , released in 2015. “I wanted to sing,” Talbot says. “I wanted to sound like Otis Redding but I didn't; I sounded out of tune and shit. We were trying to sound like a different band every week, just to find our own voice. Then we started writing this music that was angry and visceral and we all became enthralled by it.” Welcome is very much the band in their identity-forming period, a little safer and more indie while on Meat the band begin to embrace the grit and growl that would go on to define Brutalism.

We then get fancy ice cream, then lose ourselves an immersive light and sound exhibition in a gallery. In between, the band pose for photos on the street, seemingly incapable of behaving seriously for a single one. And so despite the plain-speaking, ‘we didn’t give a shit’ lines and in-person goofery IDLES aren’t a product of nihilism. They aren’t a corny punk cliché giving the middle finger at every turn. They’re self-aware and somewhat content, having given up on trying to be ‘cool’ and instead they embraced their weaknesses. “We're trying to be more naive, more simplistic and more vulnerable,” Bowen begins. Hopping on the train of thought, Talbot goes on: “I think vulnerability is key to opening the door. We want to convey something that encourages people to be naive with us, so we can get through a time that is fucking shit for all of us for different reasons.”

Bowen is calm and measured in conversation, pausing often, while Talbot’s more instantaneous responses tend to tumble out intense and profanity-laden. “I’ve got a fucking savage patience problem,” he tells me at one point – something I see later when the band are transitioning into the next song onstage and he snaps, “Ándale, ándale!” or when he darts out in front of traffic to catch the last second of a green light at a crossing. Their conversation weaves together, with each almost finishing the other’s sentences as they follow along a particular strand in our chat.

The harsh thrash of IDLES’ music may seem antithetical to a sense of hope and optimism but they’re alright with conveying a sort of open-faced earnestness. “I'm not asking people to riot, I'm talking about turning a wall of death mosh pit into a wall of hugs,” says Talbot. “In times of turmoil people want to feel like part of a community, they want to feel safe.” If creating a “wall of hugs” sounds like an overly-ardent ideal, that’s because that’s exactly what IDLES are shooting for. The band kick-off every show with kisses; Talbot goes from bandmate-to-bandmate and sticks one on their lips.

After show number two, we’re outside gallery space-turned-venue Flowers for All Occasions. As the post-gig sweat clinging to Talbot’s T-shirt turns icy in the Brooklyn night and he exhales clouds of vanilla-pudding vapour, he stops to accept handshakes and congratulatory slaps on the back from fans. He then continues to try and sum up the role of IDLES, and turning violence into love at a time when politics feels like it’s going to shit. “Nationalism is rife, right-wing politics is rife, the left is fucking sectarian and I just want to go: ‘shut the fuck up.’ A political utopia is at the end of a road, all you have to do is get on a bus.” As Talbot often likes to do, he then slips into a big, impassioned, metaphor-filled diatribe in order to depict the void he feels exists between the left and right in UK politics.

“The problem is, the right-wing politicians have already bought the fucking bus and the left-wing politicians are stood outside the bus arguing about what it should be called. You can't learn without listening to each other, it's not left and right, it's about a lot of people who are scared and confused and need unification.” He doesn’t necessarily think IDLES alone can magically cause that unity – that would be ludicrous. But, he says, the best they can do is play “with as much passion and compassion as possible in the hope that the crowd will see that vulnerability and naivety in what we do, so they can come and just let go for 45 minutes.” Well, as long as you don’t try to slag off the NHS.

IDLES play Rough Trade New York in Brooklyn on Saturday 24 March, then a load of sold-out UK dates in April that you can find out more about on their site.