Johnny Mackay has been lying to me. Five years ago, when the electric frontman of Children Collide had only two EPs to his name, he told me “If we’re still going in five years, we won’t sound a thing like we do now.” As it turns out, some of the material for Children Collide’s sophomore record, Theory Of Everything, harks back to the Very Early Days of the band. Which means someone’s been telling porkies.

“It’s funny that I would say that,” muses Mackay, “we’ve turned into this very non-linear band when it comes to treatment of time and songs. I’m pretty much always plagiarising myself!” Johnny offers the concession that “I knew I was going to be lying but I also knew it would give me something to talk about. I didn’t inhale, that’s all I want to say…”

If it sounds like Mackay is full of it, you’re on the right track. Unfortunately, their latest video clip for triple j-feted single Jellylegs has proven otherwise. For the uninitiated, the somewhat unnerving footage involves Mackay getting a laryngoscopy. In layman’s terms, he stood for eight minutes (or two runs of the song) with a camera tube down his throat. And apparently, there was nothing strange to be found; “luckily I’ve got a clean bill of health on my larynx, but I did come out feeling like I’d been invaded.” It is suggested to Mackay that he use future video clips to further supplement free medical treatment; third single, colonoscopy, fifth single, MRI, that sort of thing. “They should definitely start getting more surgical procedures into music videos,” says an understandably wary Mackay. “It’s a great way to get inside the band.”

Speaking of getting inside things, some recent publicity shots of Children Collide festure the trio mucking about with what seems to be a stuffed kangaroo. Clearly that’s symbolic of something, right? “We thought we were going to be riding the kangaroo. Nobody told us it had been to the taxidermist’s. Thanks a lot Bindi!” As it turns out, there is a method to Mackay’s seemingly unrelenting madness; “Well, kangaroos are one of only two animals in the world that can’t walk backwards,” he explains, “So it’s really about moving forward. We kind of inspired Julia Gillard’s entire campaign.”

So there you have it, Theory Of Everything, via some stuffed local fauna, is actually all about Australia, “not in a Crounalla sort of way, perhaps more generally.” It is at this point that Johnny can safely announce, “we’re all about Melbourne bush. That’s actually the precise genre of music that we play.” As it turns out, those wailing ‘90s guitars, pounding punk drums and limber basslines that characterise Children Collide’s sound were just crying out for this form of classification. As the band gets tighter and the songs get stronger, the alt-Bush stylings of the trio become more apparent. Try not to get local Penthouse centerfolds from the 1970s on the brain. This is all about patriotism, people.

Now that Theory Of Everything is in the bag and Mackay has returned from recording with legendary producer Rob Schnapf (Beck, Elliot Smith) in L.A., he’s got a lot of time on his hands. To stave off the boredom, Johnny spends his days in Melbourne creating all kinds of bizarre things that are necessary to a rock musician’s survival in this harshest of climes. He’s already locked down a number of different patents, so many indeed that he actually created Children Collide as a secondary name to put on the documents.

Among these varied inventions are, allegedly, air-conditioned pants, designed during the Big Day Out heatwave of 2009. “Westinghouse and I have been working on this collaboration for some time. There’s little units in each leg of your jeans, which keeps you firmly planted on the ground.” Add that to the new musical genre, medical-informative music vids as well as Johnny’s unique plan for passing out on planes (“Eye mask, ear plugs, hoodie and half a sleeping tablet”) and you’ve got one busy front man. But new fans of the band have only recently discovered by far the best thing Mackay has invented. “I keep getting people asking me about the effects on the guitar,” he laughs, “but it’s just distortion and I’m playing fast! People might say I discovered it, but we don’t have to brag about it.”

Theory Of Everything marks the culmination of a new chapter in Children Collide’s career, as Johnny has a minor freakout and realises that fans may actually know some of the new material. As their sound becomes more cohesive and moves out of the apartment (where they used to record everything) and into proper studios, Children Collide are starting to appear like the popular rock band they were almost certain they’d never ever become. For the first time in the interview, Johnny doesn’t lie; “It’s all new territory to me, because up until about a year and a half ago, almost all of our songs felt kind-of unknown,” he says. “Sometimes people even sing along to our songs now!”

Naturally that will have changed if Labor doesn’t win the election and Children Collide are hounded out of Melbourne. Which is why Johnny’s got some contingency plans, including putting his stuffed kangaroo on wheels so it can finally move backwards. He’s even asking at what point in the album interviewers get bored and turn it off, so that he can get back in touch with the people. “ Future Monks is one of my favourite tracks, but that’s at the beginning,” he laughs, “My attention span isn’t that great, either.” They may be more layered and widescreen, but one thing’s assured with Children Collide; their tracks will always be punchy and to the point, even if they aren’t as mind-bendingly fast as they used to be.

Or is there a change in the air? Despite gearing up for a nation full of easily distracted kids, Mackay maintains that if he had it his way, “I’d love to record an album that’s just one, forty-five minute song. It’d be pretty funny for the guy who takes it to radio to have to go into Nova… we could do an acoustic version of the forty-five minute song just for them.” As it turns out, Nova has some sort of fifty-minute ad-free deal going at the moment anyway, which will now be entirely full of Children Collide. Clearly the master of patents is at it again. But don’t believe Johnny Mackay. He’s just a filthy liar.

Children Collide’s Theory Of Everything is out now; and the band is on tour throughout September