A proponent of the power of positive thinking, Van McCann is a young man of unabashed ambition. He's not immediately certain where Catfish And The Bottlemen played last night – "We're driving across from... Christ, I can't remember where we played... Denver! We played Denver last night!" – and he's calling from "literally" the middle of nowhere, but one thing of which he is sure is that his band and their no-nonsense indie rock are going somewhere fast. If you could boil his outlook down to a mantra, it would simply be "why not?", a phrase he tosses out cheerily and frequently over the course of our conversation, along with "dead exciting" and other upbeat superlatives. In the midst of a US tour, the future in his mind's eye is big and bright, full of opportunity. And why not, when you're frontman of a Welsh quartet who have gone Top 10 in the UK with their debut album, 2014's The Balcony, picked up a BBC Introducing Award before Christmas and kicked off this year by appearing on Letterman?
The first major fruits from many years of effort for McCann, who made music his full-time concern after getting kicked out of school for truancy at the age of 15, and it's only the start. There is also plenty of vague talk of a "takeover", to pinch a phrase from a particularly big sports personality from Ireland. Indeed, if McCann claims he's "thinking about writing songs all the time", the Dubliner known as The Notorious MMA is also in his thoughts of late.
"Mate," he ventures halfway through our chat. "Are you buzzing off that Conor McGregor? D'ya like him? Mate, he's gonna be champion of the world! I love him! If you see him, tell him me and the lads love him. He's just a machine. He's gonna take over, proper. I was in New York and I met a bar maid who was Irish and I asked her what she thought of him. She was like [adopts begorrah and begob comedy Irish accent] 'ah, he's a bit of a gobshoiiite! you don't know, he could get his mouth shut!'
"But I was like 'no, he's gonna take over! Believe! He's gonna be the champion of the world!'
He's just far out. He seems like he goes the extra mile. He says 'I put in five hours longer than everyone in the gym.' I love people who speak like he does."
McCann, who is aware that he can cause journos' eyes to roll when he starts talking about wanting to be "the biggest band in the world" but still can't help himself, such is his ebullient, wide-eyed nature, agrees that he recognises something of McGregor in him. The ambition. The work ethic – despite leaving school early, he was determined not to end up as a "dosser" and bring shame on his family.
"I think that's what it is. Also, 90% of the time Noel and Liam [Gallagher] are obviously taking the piss. They're joking. McGregor does that. You know when he's like, 'three men died making this watch! An elephant died making this suit! There are only two things I like doing: Looking good and kicking ass. I'm doing one now and I'm going to do one on Saturday!'
"I just love that attitude of: I'm from Ireland. I'm not a big shot. I don't think of anyone. And when I'm on the beach I train my arse off. And now I'm gonna fucking take over the world!’"
Muscle Beach crunches aside, Van could be talking about himself. Born in Australian to Liverpudlian parents and raised in Wales, as you would assume from his surname, he has Irish heritage (his first name comes from his father's love for Mr. Morrison).
Catfish And The Bottlemen – that moniker was inspired by a Sydney Harbour busker McCann saw as a kid – reach Irish shores for a couple of shows in March and Van expects them to be akin to a big family reunion.
"Honestly I think half the tickets are gone because of my family alone! We get asked a lot for guest list by people we've never met: 'oh I'm your cousin, I've loved you all my life!'”
You can trace his performer's gene back to his grandfather, who still plays in an Irish jigs in folk band.
“My dad text me the other day to say my granddad's out on the second leg of his tour,” Van laughs. “I'm like 'what?!' This guy must be 200 years old man, he's a machine!"
Of a generation that apparently “never really heard of rock ‘n’ roll”, he only clocked the extent of his grandson’s success on the scene when he learnt Catfish And The Bottlemen had been signed to Island, the same label as U2.
“So then I could phone him and go 'Grandad, you know Bono?' and obviously he knows Bono… He's called Jerry McCann but I call him Jerry Hendrix because he's a king on the fiddle. He's brilliant.”
Van concedes that the fiddler might not know the music, but he’s likely more rock ‘n’ roll on tour than the young pretenders. "Oh yeah, my family were crazy long before I came along!" Van likes meeting new people on tour (“I'd much rather go into a gas station in LA and meet someone cool than go up the Hollywood Tower and take a photo of it”) but you’re most likely to find him lost in music in his dressing room on the day of a show. And he won’t have company. “It's not like ‘oh yeah, let's go meet a fan round the back’ or anything like that. We're not really into that stuff.”
Indeed, the life of a musician with goals sounds positively monastic.
“You can't hold anything down. My best mate is our guitar tech. You can't even have proper mates anymore because you're never there to have a beer with somebody. You only see each other every seven months or whatever. It's mad. The past year's been hard for me because of all that stuff. Now it's got to a point where it's like: ‘It's all about the music. We've got to take over, before anything. That's what I’ve always promised my dad and my grandad and myself. And anybody I've ever met.’”
On paper, it reads positively Borrell-esque, but Van somehow manages to consistently treat any potentially off-putting Razorlightitis with naïve charm. He’s more like someone’s eager-to-please younger brother than pouting poseur with a high opinion of himself. So for every “The new stuff I've been writing has been making our manager cry” comment, you’ll get an endearing musing such as this: “I think people like us because we're that gobshite, shit band that you see in the pub every weekend who are playing Stereophonics covers... But we got good!”
Melody-heavy mini-indie anthems such as ‘Kathleen’ have helped swell their fanbase, though a UK publication or two has dismissed the quartet as being a decade too late, chasing the now-distant coattails of mid-‘00s guitar bands.
“Magazines won't touch us. We've got no angle, we're just the same band that comes along every 10 years. What can you say about us? ‘They wear all black. They've got long hair like The Ramones.’
“When I was 14 and was doing local press,” he continues, “Even to our local paper I was like 'we're going to be the biggest band in the world! Why not?! We're gonna go for it!' That was when we were just doing Stereophonics and Beatles covers in bars. I don't go out with a girl unless I think she's the one. What's the point? Why bother? If I was going to have a kid, I'd want to be the best dad in the world. If I was a bin man, I'd wake up an hour earlier than everyone and clean all the shit up. With the English press, the natural thing is for English people to go 'who the fuck does this guy think he is? He's not going to take over the world.'”
Ireland feels more receptive. Van might struggle to figure out his current American co-ordinates, but he’s thought very carefully about his band’s plans for his ancestral home.
“I was like 'why don't we take over Ireland? Why don't we become the biggest band in Ireland?' If you get fucking Ireland on your side – the Irish are everywhere! And it's in me. So I reckon they'll love me! I'm related to them! They can see it in me eyes! One of my family told me they read an Irish paper say to come and see us play because the next time we were over, we'd be playing stadiums. I was like 'fucking hell!' because the English press don't write about us like that: ‘The Irish think we're going to be U2, it's mad!’ If there's one person in Ireland that thinks we could be U2, then I'm going for it!”

Catfish And The Bottlemen play Longitude in Marlay Park, Dublin, this Friday July 17