IF you’re a writer and you find yourself in an office working on a comic strip called Poo Crew about “eight or nine jobbies lost in a sewer,” it is just possible that you may feel that you have reached something of a low point in your career.

Especially if, while you’re sitting in an office writing said strip, someone asks you if you’ve written for comics before.

“I said Judge Dredd,” David Baillie remembers. “And he looked horrified. ‘Why are you writing Poo Crew?’

“That was maybe a career low,” Baillie admits, laughing, “but even it wasn’t that bad.”

Because the simple truth is the job of the writer is to write. And if that means writing a comic about talking jobbies, well, so be it. Truth is, he’d taken some time off after the birth of his daughter Isla, he needed a job and Mega magazine offered him one. “It’s a really good magazine,” he says. And, anyway, he loved the idea of writing for kids.

All of which is fair enough. But I have to ask, David. Is Poo Crew on your CV?

He looks at me across the pub table and admits that no, it is not.

It is August in Edinburgh and Baillie, now 40, is in the capital for the book festival. He has travelled up from his home in London where he lives with his wife Ang and his daughter Isla. When we speak Baillie is back working on Judge Dredd and from time to time talking to TV people about this and that, most notably his recent comic strip, published by Vertigo, DC’s mature imprint, Red Thorn (of which more in a moment).

Baillie makes for entertaining company. In our hour together conversation ranges leisurely from the realities of a working-class childhood in Whitburn to the surrealities of investment banking and what it means to be a writer now that the geeks have inherited the earth.

Truth is, he himself has always been in their number. There was a time in his teens when he’d be going to comic conventions just to try to sell photocopies of the comics he had written and drawn himself. Next month he is a guest at a comic convention in Kilmarnock where he will talk about how he got from there to here.

Red Thorn is the reason I wanted to talk to him. It ran for 13 issues in 2015 and 2016 and has now been gathered up in two paperback collections. It is a colourful mix-up of Celtic myth and Caledonian reality, located, as it happens, on the River Clyde.

Red Thorn moves a cast of ancient Gods and mythical characters through real-life Glaswegian settings. There are pubs you will know, (the Barrowland) and, appositely enough given that it’s full of blood and gore, the odd graveyard (in this case, the Necropolis). And there is rain. A lot of rain.

No surprise given that when sending photographs to Red Thorn’s American artist Meghan Hetrick, Baillie tried only to send pictures where the rain was battering off the pavement because “this is what Glasgow actually looks like.”

In the pages of Red Thorn you will find kelpies and the Loch Ness Monster (not quite as you probably picture it) as well as lesser-known creatures from Celtic mythology. Creatures such as Redcaps who guard the borders and dip their hats in the blood of trespassers and the Shellycoat, a bogeyman who wears a “stinking coat of rotting fish”.

There’s also an American heroine called Isla (sound familiar?). Oh and a protagonist who has magic powers, a six-pack and the look of … Well, isn’t that Ewan McGregor, David?

“It’s not meant to be Ewan McGregor. But the editor-in-chief at the time, was very into mood boards and I can confirm that Ewan was on the mood board. McGregor, a young Mick Jagger and Adam Ant. She was a big Adam Ant fan.”

McGregor would make good casting if it was ever to be made into a movie or a TV show. “We’re talking to TV guys and the name they all mention is James McAvoy. I don’t know if that would ever happen.”

How did he get here? In many ways you could argue that Baillie’s story is the perfect example of a self-realisation narrative. He has willed himself into the position he now finds himself in.

He had a “very average working-class upbringing” in Whitburn in West Lothian, a mining town where the pit was shutting down. “There was a lot of unemployment. It was quite tough-going.”

His father was in the navy, his mum a home help. But at school Baillie was clear he wanted to be either a writer, artist or computer programmer. His careers advisor was not sold on any of the options.

“She’d never met a computer programmer - I suppose it was a bit early in the tech curve for that - and had never met a writer or an artist. I think at one point she was going to have me drive a truck.”

Still, the idea of being a writer persisted. “It seemed completely unachievable but it was there as a distant goal. Everyone else wanted to be a football player and I wanted to write and draw comics.”

He went to university aged 16 to study electrical engineering, before leaving for London in 1999 with the intention of finding a job that would pay him enough to allow him to quit and become a writer.

Amazingly enough, he found one. Working as a computer programmer in an investment bank. He didn’t much care for it.

“I didn’t like the work and I didn’t like the people,” he admits. “It was very unpleasant. So I handed in my notice and they gave me a pay rise. So I said: ‘OK, I’ll stay another few months.’

“And then I handed in my notice again and they gave me another pay rise. We did this for two years and by the end I was on an insane amount of money, more than what I was worth. If I’d taken the last job contract I was offered I might have been a millionaire now.

“The key to investment banking as far as I can make out is keep handing in your notice until they offer you an incredible amount of money because they think they’re missing out on something.”

Instead, he walked away with some cash in the bank and started to pursue a career as a writer. “It took a year until my first paying gig and my bank account was dwindling down. But it was good.”

His first paid story was for a four-page strip in 2000AD. “It’s embarrassingly bad. But it was just good enough to get my foot in the door.”

Work on licensed comics such asTeenage Mutant Ninja Turtles followed and some storyboarding for children’s TV on programmes such as Tellytubbies and In the Night Garden, before he eventually was able to parlay his 2000AD credits into a chance to work for Vertigo.

“It took me a while to work out how the American system worked. All the British people go out in one big wave to New York and San Diego [for conventions] and then they sit in the pub together. No one networks at all.”

So there was a measure of luck about his breakthrough. Shelley Bond, editor in chief at Vertigo (the aforementioned Adam Ant fan) called him out of the blue and told him there was a bit of a buzz about his name. “And the funny thing was there really wasn’t.”

But he had just been followed on Twitter by one of Bond’s fellow employees whose grandfather was Scottish. Baillie had asked him if he could send him some story ideas. At the same time Baillie’s name was mentioned in dispatches by another British writer Mike Carey. Meanwhile, artists looking for work with Vertigo had submitted some 2000AD stories to Bond which Baillie happened to have written. All of this came across her desk in the same week. It was a complete coincidence.”

It helped, too, that Bond was something of an Anglophile. “She is married to an English artist and when I met her for the first time she wanted to talk about EastEnders.

“I had to tell her off a few times. She said she loved comics set in England. ‘But Shelley this one isn’t set in England.’”

Once his proposal was accepted he got an insight into how the world of comics works in America. “There was a lot of back and forth because DC is owned by Warner Brothers and they look at everything that comes in the door and there is a movie guy, a TV guy, a computer games guy and a merchandise guy and they all had a bit of advice.”

Red Thorn was two years in development. He spent that time knocking out drafts which would go to the film department who would tell him: “‘This bit isn’t like a movie.’ Well, no. It’s set in a pub in Glasgow. It’s three men having an argument over a pint.

“What I wish I had known at the time is you can tell these guys whatever they want to hear and the do what you want because they don’t read the comic.”

The comic is finished now but Warner Brothers still have an option on it “and there is interest,” Baillie says. So it’s possible Red Thorn might make the transition to the big or small screen in the way that other Vertigo titles such as Preacher and Lucifer have in recent years. But Baillie is not holding his breath.

“I was talking to the artist Steve Dillon shortly before he died and he said it took them 25 years to get Preacher off the ground. He said: ‘You could be a very old man before it happens.’”

If it ever does, maybe then Baillie will start to make up for all that investment banking income he passed up. Not that he sees it that way. “Financially I made a bit of a sacrifice, but I wouldn’t have been happy so it’s not really a sacrifice. I get to do what I love every day.”

He looks positively flushed with happiness as he says it.

An Audience with David Baillie takes place at the Dick Institute, Kilmarnock on November 18 as part of Comic Con.