That, he says, is the nature of street art. You put it up - sometimes undercover, although this one was created with permission - and hope that it will start a conversation before the next person comes along and covers it up.

But this mural, which went up in late July, quickly took on a life of its own.

Cornish, the Canberra-born stencil artist who also goes by the name E.L.K, was commissioned by the local council to create an artwork by the sea to coincide with an exhibition of his work at the adjacent Bondi Pavilion.

He was given free rein to paint whatever he wanted. The resulting work - a row of 24 gun-toting Border Force officials, to represent the 24 suicides in Australian detention facilities since 2010 - was bound to ruffle a few feathers.

And the words "Welcome to Bondi" above the figures, with "Not" painted red before the slogan, made the artist's intentions clear.

"It was the perfect opportunity to make a statement in such a public place," he says.

"I had about three days to prepare it, so I just needed one stencil that I could replicate over and over, with the message at the top. I knew it was going to be a comment on immigration, our treatment of asylum seekers. All the stars aligned, it unconsciously ticked all the boxes."

But within days, a local Liberal councillor called for the mural to be removed, only to be roundly shouted down by supporters, hundreds of whom signed a petition calling for the mural to stay. The council, with the support of the local mayor, decided against its removal.

Hours later, after nightfall, someone painted over most of the mural with smears of white paint.

"It came out of nowhere, the shitstorm," Cornish says.

"I knew it was going to piss a few people off, but I didn't expect it to be starting a national debate.

"It was on BBC news, and on Der Spiegel in Germany, I had people contacting me from all over the world."

Consequently, he says, the past few weeks are now "a bit of a blur". The now-battered-looking mural has become something of a shrine, with people writing messages of hope and leaving flowers as tributes to the very people Cornish had hoped to give voice to with the work.

"It genuinely did start the conversation that I wanted to have," he says.

"The conversation was hijacked a little bit there, and it became about free speech, and I've already got free speech, so I don't need to talk about that. It's kind of been diverted back to what I'd originally hoped to be discussing.

"Absolutely, that's my role as an artist, to raise a mirror to society."

In the meantime, though, he's been busy preparing for a new exhibition of his work, due to open next week at Ambush Gallery here in Canberra. Made up of two bodies of work, many pieces in the show will reflect his first-hand experiences in war-torn Syria, a region he has visited three times in the past three years. It will also speak to the recent Bondi debate.

But first, he says, he'll be coming home to stage it. No two ways about it, he's a "proud Canberra boy".

Born at the old Canberra Hospital, he went to several schools on the northside, but while he always had an artistic bent, he never went on to study art.

"I'm self taught. Art school was never really an option for me," he says.

"I was just in that Canberra thing where you go to school and then you stop going to school, and you start working and you get buried in a mountain of debt, trapped in that cycle for years.

"Art was always something I did on the side, because I worked a lot of construction jobs, nothing I was ever passionate about.

"But eventually, the art started taking over, and I started to take days off work to do projects, and eventually it just became so much that I was doing it full-time."

It was while he was studying horticulture, with plans to be a landscape architect, that he discovered stencilling by accident.

"I remember doing a project, a garden design, and I didn't have any blue pencils," he says.

"So I cut out this template and spray-painted this blue over the top for the sky and took it off, and went, f***, that is so cool. I'm going to go home and do more of this stencilling stuff."

Incredible, he says today, how an entire art form could be stumbled across so randomly.

"It just fascinated me how immediate the process was. So that opened a Pandora's box, and I became obsessed with this technique."

It's no wonder, then, that when one of his works was a finalist in the 2012 Archibald Prize, it was something of a sensation. It was the first time a street artist had made it into the finals, and the work, a portrait of outspoken Catholic priest Father Bob Maguire, was timely; Father Bob had recently performed his last service, having been controversially forced to retire.

"That was insanely monumental," says Cornish.

"That was the first time I'd ever entered, actually. The media attention was quite confronting because I'd never experienced anything like that before. I wanted validation as an artist, but it all came at once, it was such an amazing ride."

He's strangely relieved that his entry this year, a portrait of entrepreneur Sue Cato, is a finalist that has received next to no attention.

"That largely went under the radar, which was really nice," he says.

Although he has always worked to make his mark as an artist, he has never sought the type of validation that, he says, so many of his contemporaries seem to crave.

He honed his skills alone, and without many outside influences, while still living in Canberra, and waited years before moving to Melbourne to establish himself as a street artist.

"I think there's always been a political bent to my work, whether that's subversive or not, but I think maybe a lot of that comes from being surrounded by politicians in Canberra," he says.

"Also, not having any real outside influence of the larger street art world - it's very sheltered in Canberra. I think that really allowed me to develop my own style.

"It was very serendipitous, there was no 'I want to be like that person', it was more, 'This is something I want to do for myself', not trying to get recognition.

"I think a lot of artists become quite bitter when they haven't made it, but I think if you're doing this to make it, you're doing it for the wrong reasons."

Still, it was a good time to be getting into street art. These days, and especially in the wake of the Bondi mural, he's being compared to the anonymous English-bases street artist Banksy. But Cornish was busy honing his craft in the pre-internet era - "before anyone knew who the f*** Banksy was" - and it was in the mid-2000s, around the time of the Iraq war, when stencil art became the perfect medium to express a growing collective frustration.

"Stencil really gives a very fast, immediate way of getting a message out there. There was this huge boom of stencil art in Melbourne, and that's when I became even more obsessed with it," he says.

He says it took just three months to establish himself in Melbourne. He stayed there three years, and then moved to Sydney, where he has lived for the past seven years.

"Moving to Sydney was really about transitioning into the contemporary art world and trying to make a name for myself there, which took a bit longer than three months," he says.

Today, he is one of Australia's best-known street artists, as much for his work as for his way of gathering material. The exhibition at Ambush will be largely informed by his trips to Syria over the past three years, where he has immersed himself in daily life, and learned what it's like living in a war zone.

He had always wanted to be a war artist; one of the first art exhibitions he ever saw was one by George Gittoes at the Drill Hall Gallery in the mid-1990s.

"I'm still waiting for the War Memorial to give me one of those. That's kind of what I was hoping for, but then I thought stuff it, I'll do it myself. I'm not going to wait for permission," he says.

But, he says, having now spent time in Syria, he says doing an approved residency would feel "positively boring" in comparison.

"I've been arrested by the Syrian Arab Army, I've had guns pointed at me," he says. "It's a different level of fear, and when something's so far out of your control, you just relax. It's very hard to explain, you just kind of go with the flow. If you can't control it, you just go with it."

In the midst of dealing with the Bondi fallout and preparing for this exhibition, he has also split with the two galleries - Metro in Melbourne and Nandahobs in Sydney - that have been representing him and his work for the past several years.

"There's no animosity, I consider them all very good friends, but ... I feel like I'm making what people want to buy, I'm making what's going to sell, I'm making what the gallery's going to like, I don't want to upset anybody," he says.

"The quality of the work is becoming more and more mediocre, and it's making me a little bit miserable, actually."

"I've pretty much once again said goodbye to financial security in order to do what I want to do. But that's the gamble I took when I decided 10 years ago to do this full time, and it worked out fine, so I'm not too worried about it."