PHILIP Miller has a problem with the elevator pitch for his new novel. In fact, he hasn’t got one. He knows what one is, of course: you don’t get to be the Herald’s arts correspondent for the last 13 years – never mind being married to a film director for half of that time – without knowing that. Indeed, when I ask him, he gives me one of the best examples around. “You mean, like pitching Alien as ‘Jaws in space’?”

“Exactly. What’s yours for All the Galaxies?”

“Well,” he says, “when I first started, I knew exactly what it was about. But when my publisher asked me, it took me about five minutes to tell him. It’s quite complicated.”

There’s a three-second silence. “Essentially, it’s a series of searches.”

I look across the table at him. He looks back. Open-faced, slightly apologetically. He’s probably wondering what kind of intro I’m going to write for the interview, doubtless hoping that it’s not going to be one like this.

Because, let’s face it, “a series of searches” is lame. It could apply to so many novels. And when you have written one set partly in the afterlife with a boy and a talking dog flying through galaxies and partly in a near-future Glasgow city-state beset by nihilistic terrorists, it hardly cuts the mustard.

Compared to the intergalactic travels (“billions of miles in seconds”) of the boy and his Border terrier spirit guide or the Devil’s rise to power in Glasgow, the third element of the plot – the terminal decline of the city’s newspaper, where the boy’s father works – seems positively mundane. I’d say small beer were it not for the fact that the staff on this fictional newspaper, the Mercury, are awesome boozehounds, and so drunkenly hot-tempered that fist-fights in the newsroom and drunken attacks on civic dignitaries are not unknown. Ned Silver, its shambolic arts correspondent, is hardly the worst culprit here, though he can be relied upon to be hungover in the mornings and upside down behind the jukebox at the end of the night.

Surely, I venture, this is all a bit parodic? Miller, 43, equivocates. “Exaggerated maybe,” he concedes. Of course, he adds, a dying newspaper mirrors his dystopic picture of Glasgow and the imminent end of its print existence and plans for its continuation online has some small echoes of the book’s other theme of death and afterlife. Perhaps, but I’m guessing that there’s also a certain pleasurable frisson in saying the officially unsayable under the cover of fiction.

No, he insists. The Mercury – where corporate memos talk sludgily of “replacing ballast staff with engaging citizen-journalists already embedded in communities for cost-effective hyper-local reportage delivery nuggets” – is not a thinly-veiled Herald. He points out that since he left Edinburgh University, where he read history, to train as a journalist, he has worked on three other newspapers – the Glaswegian, the Scotsman, and the Sunday Times Scotland. “At every one there have been reductions in staff, changes in editorial systems and general convulsions. Only in my first couple of years in journalism, before the internet started to kick in, did things feel vibrant and healthy on newspapers.”

But it’s the impulse to, in Robert Lowell’s phrase, “make something imagined, not recalled” that drives All the Galaxies. The core of the story isn’t the Mercury’s last days in print, or newsroom memories, but the boy’s afterlife journey across time and space guided by his pet dog. Why did Miller feel the need to depict the barely imaginable – the two intergalactic travellers’ journey through an exploding supernova, for example – “all around was a splintering vortex of nuclear power and heat beyond reason and conception” – rather than focus on the small details of lived lives? Why did he want to make his Glasgow the battleground between a stigmatic former priest and a devilish city manager, a cauldron of purposeless violence?

“I have never felt constrained in either my reading or my writing,” says Miller. “The Blue Horse [his 2015 debut novel] was more restrained and all set within Edinburgh and the art world. From the start, I knew that this one was going to be on the widest canvas of all – infinity and eternity. I also knew that if I was going to devote such an amount of time to writing a novel I didn’t want to write anything that is compromised in any way; I wanted it to be something that is completely me and comes from my own head.”

Writing All the Galaxies, he sometimes shocked himself with the minutiae of his dystopia. Indyref2 has failed a while back, but the novel’s violence is essentially politics-free, and he found himself casually dropping into the narrative axe attacks by tattooed terrorists on the Kingston Bridge, for example, or mass shootings in Edinburgh. He tried to be similarly specific in the passages about the afterlife: “I wanted everything to be crystal-clear, not wishy-washy or how you see the afterlife in so many films, you know, with diffused lighting.”

You can almost hear the self-certainty in his reply, and given his agnosticism about the afterlife – “it depends what day of the week you ask me” – that might sound surprising. But Philip Miller (he’s “Phil” in his newspaper byline and to friends; “Philip” in his poetry and novels) knows exactly what he’s about. In the afterlife, he wants the boy and his dog to register every detail of the universes they speed through (“Far below slowly spun the vast dish of another galaxy. It was berry-red and melon-pink”) and the creatures who populate them (“In the far distance, on a peak, a huge dragonfly-whale-eagle creature was perched... The wings – even 100 miles away or more – were huge, iridescent.”)

He has always, he says, had a vivid imagination. Growing up on a council estate in County Durham, he made up stories for his younger sister (“fantasy mostly”) as a child, although it was only in his thirties that he seriously tried his hand at writing short stories. He had started All The Galaxies even earlier, in the 1990s, “but although the plot also had the concept of the devil ruling Glasgow and a central character who was a journalist, it wasn’t working and I lost heart.

“I had the afterlife scenario in my mind for a long time too. I imagined it as a secular afterlife, in which people might be in new bodies which were then inviolable.” The closing scene of Terrence Malick’s film Tree of Life – in which the dead return to life and are reunited with their loved ones – was, he says, a particularly strong influence.

Film means even more to Miller’s wife Hope Dickson Leach, the writer/director of the feature film The Levelling (out on general release in May) who is already being talked about as “an exciting new voice in British film-making”. It was only when she was away for nine weeks to shoot the film on location in Somerset that Miller’s novel came together. He took that time as a sabbatical and stayed behind in Edinburgh to look after their two sons, aged four and six. This was when he ploughed ahead with the first draft of the novel, pressured by that nine-week deadline: “I figured if I didn’t write it then, I never would.”

The news that year was full of jihadists and beheadings and drowning migrants, and maybe that’s the seed of reality that sprouts into the horrors of the random violence he imagines in Glasgow. Into the mix went Kim, the border terrier he had as a child (the only “real-life” character to make it into the novel), stirred in with a couple of already written short stories about Fallon, the boozy Glasgow newshound who is one of the novel’s key characters, seasoned with a pinch of David Peace’s incantatory style. Writing “while in the kind of fugue state where you can write for hours and time goes into abeyance”, an essentially improbable mixture started to make some sort of sense.

Enough sense, at least, the next time he is asked for an elevator pitch for All The Galaxies, for him to be able to say: “Easy. It’s about love, death, Glasgow, newspapers, infinity and beyond.”

All the Galaxies, Philip Miller, Freight, £9.99