Last month, nine scathing new murals cropped up around Paris. A mourning veiled figure outside Le Bataclan gig hall. A young girl painting over a swastika. A rat with a bow-tie on its head. An obvious critique of the French government’s crackdown on immigration, fingers were immediately pointed at world-famous street artist Banksy, who later confirmed his responsibility on Instagram.

Known for his large-scale art, for decades, the anonymous Bristol-born artist has pervaded the public eye, whilst still placing poignant and timely graffiti in very, very public places. And now his original gallerist, Steve Lazarides, and Mayfair’s Lazinc gallery co-founder, Wissam Al Mana, have teamed up to showcase some of the artist’s most iconic and earliest works, all in one place.

Curated from a number of private collections, the exhibition includes stencilled canvases, sculptures, paintings, and limited-edition prints – many which have never been exhibited in public.

We chatted to Banksy’s original gallerist, Steve, about how they met, selling his art out of the boot of his car, and why the international man of mystery became anonymous in the first place…

Hi Steve! Why was now a good time to do a “Greatest Hits” exhibition?
I met Banksy almost 20 years ago and he’s been around for much longer than people think. Now just felt like a decent time for a show of his greatest works.

How did you guys first meet?
I took his portrait for an old-school style mag called Sleazenation. We were doing an article on Bristol and even though both the editor and I were probably a generation older than Banksy, we’d started getting word from different people that there was this new kid on the block. So we went down to meet him and that’s where it all started. I took his portrait, became his documenter and then his gallerist.

I heard you started out selling Banksy’s work out of the trunk of your car…
That’s true. It’s funny looking at some of the paintings here that are now worth half a million and how many of them used to be slung in my old Saab. Back then pieces just weren’t worth that kind of money. They were worth 250 quid, so it’s quite weird how people change their perceptions. But to me they’re still 250 quid paintings!

How do you think his work’s progressed?
I think his street work has become a lot more political and targeted. Even though we haven’t spoken in a decade, I still follow what he’s doing. He doesn’t seem to do as many paintings any more, and if he does, I think they are commissioned to come out of the studio. Back then, there were corrupted oils and stencils in each show he did. He owned the zeitgeist and there was a kind of visceral energy to what he brought.

So you guys haven’t spoken in a decade…
We went our separate ways, but we’d worked together for a long time. Like many gallery and artist relationships, it’s quite intense, and we wanted to do different things. Instead of fighting every day, we decided to go our separate ways. But I had the absolute time of my life.

What’s your favourite image from the exhibition?
I’d say it was the “Avon and Somerset Constabulary”. It’s such an underrated piece of work. It also speaks volumes about why he became anonymous in the first place, which is because he was prolific across the streets of Bristol and was constantly being chased by the Avon and Somerset constabulary. It’s one of the earliest pieces I remember seeing of his.

How do you think street art’s changed?
Fifteen years ago, we were getting chased out of everywhere we went. Fast-forward 15 years and you’ve got property developers ponying up walls for street artists to use. I think it’s ruined the movement. Artists who were painting 15 years ago were willing to risk their liberty to put those works on the street, and it took a certain type of person who was willing to do that. And they had a much more political, visceral angle. Now you now get your weekend warriors coming out, who can hire a cherry-picker, paint a photorealistic mural and take as long as they want. You go to places like Melbourne, the self-confessed street art capital of the world, and it looks awful. You’ve got a street where there are 50 pieces banged up next to each other, each jarring with the other one. And I don’t understand why people aren’t saying more politically. The two biggest artists in the world, JR and Banksy, both are ploughing a very strong political message.

Anyone to keep your eye on?
There’s a girl I really like called Shamsia Hassani, a female graffiti artist working out of Kabul. Her main image is a girl in a blue burka, which is obviously a loaded political message. And the fact she’s a woman – every time you take out a spray can out there’s a definite worry that someone might put a bullet in the back of your head.

What do you think about social media’s impact on art?
I think it’s a great thing. When I was documenting Banksy, I was still using a film camera and I’m the only one that has those pictures of Banksy’s works. But nowadays if Banksy puts a piece of art on the street, it’s out on social media and 10 million people see it. There’s no museum in the world that’s going to open someone up to 10 million viewers and make them popular in 100 different countries simultaneously. I think that’s what helped popularise people like Banksy and JR globally in a way that was never possible before.

His recent work in Paris got a lot of attention…
I’m just proud that he’s still out there ploughing the political message, because he could just go, fuck it, I’ve done enough. But I like the fact that he still cares enough and he’s driven enough to go and put those kind of pictures out there. Hopefully it will inspire people to do the same.

What do you think’s next? A “Greatest Hits” feels like the end of an era…
He hasn’t done a painting show in a long time and I’m not sure if he’ll go back and do an exhibition again. He might feel like he’s done that and ploughed that route. And if you look at what he’s done recently, it’s an extrapolation of what he’s done before, but it’s a lot more situationalist and event-based. Like The Walled Off Hotel and Dismaland.

Why do you think it’s important doing exhibitions like this?
I think people are buying into a slice of rebellion. One of the reasons for us moving to Mayfair is to get stuff like this taken more seriously. It legitimises the artists.

Banksy Greatest Hits: 2002-2008 is open now until 25 August at Mayfair’s Lazinc