Despite the sweeping psychological canvas of his work, Pat McCabe has reached the point where commentators prefer to talk about his writing in terms of simple polarities. Whether it's the bleak gothic vision versus the wild humour, the finely crafted novel versus the piss-taking pastiche, McCabe's career has inspired superlatives for novels like the The Butcher Boy, and the completely opposite and vitriolic reaction to the perceived failure of work such as Emerald Germs of Ireland.

Now McCabe has taken another creative leap and returned to his most famous novel for the base material of his new play. The Revenant sees a fifty-something Francie Brady railing against the universe, mourning the passing of his loved ones, and attempting to make sense of a life defined by one brutal act. McCabe once referred to life as "a crack between two dark eternities." If anything The Revenant is even grimmer than that, a grimy tattered flyblown lampshade of an existence between those same eternities. It's a chilling play, offering up a scalpel-clean dissection of a disturbed mind, and McCabe justifies resurrecting his most famous character by advocating looking at the bigger picture. For him it's a window into the massive changes in Irish small towns which he says "has resulted in the psychic, political and topographical landscape being changed beyond recognition. It's a sort of an oblique look at Francie Brady. In a way I don't kind of emphasise the theme of the play being about Francie. It's really a kind of way of examining these initially invisible changes."

This examination of a small town through a character seemingly left behind, so that he becomes as McCabe calls him "a ghostly displaced soul", is probably a logical progression for him at this point in his career. McCabe is now living in his childhood town of Clones, and it seems fitting that he should return to the wellspring from which he has drawn much of the inspiration for his fiction. In the play he also returns to another of his favourite themes: "The other aspect is the mortality aspect of the cyclical change that people go through. The one constant is the passing, while the landscapes change in both ways that I talk about on the surface and interior;

what's constant with small towns is the small gene pool and how the people come and go. It's about that continuum which is to some extent broken now in the small towns, but nonetheless nature continues its merry way, as always."

Small town For him the play is a mixture of two themes. While he is keen to stress the small town aspect, it's difficult to ignore the towering presence of Francie Brady, and he explains why he felt the need to return to him: "I suppose that looking at it now I wonder did I let him off the hook. Maybe that I'm older now I can see it more clearly. . . I wonder about retribution for your actions now. In a way I ended the book almost in a sympathy with him which is maybe not fair.

So now I'm looking at it thinking maybe there should be another ending. In a way that's why I'm going back to it. In his wiliness, did he fool even me? Because I'm beginning to think maybe he did."

He's aware of the literary baggage that an audience will bring to this play, but is delighted with any chance to follow his instincts and "reverse anticipation". For McCabe this play also has a broader purpose. "In a way what I've been doing is almost an assault upon the elegy, as it were. In that I've always felt that with the dying fall and the belief in humanity, and the belief in redemption, and the possibility of oneness with the cosmos, and a sort of peace descending, however difficult, and eventually falling into the arms of something or someone that it was too easy. But now I'm saying that was just a modus almost for releasing a kind of lyricism, or a kind of gentleness which I'm suggesting now is dishonest. So stylistically it's jagged, it's gothic, it's anything but lyrical. So I'm really coming at him and myself. Well, after this the audience can make up their own mind. There's totally nowhere to go after this, this is the unequivocal ending."

McCabe is conscious that Francie Brady is more than just a fictional character, and that with The Revenant he is finishing off a kind of folklore cycle that has resonated with Irish people on many levels.

The novel itself was followed by movie and stage adaptations, both of which were hugely successful.

"When you say Francie Brady now everybody knows who you're talking about. Now that's bizarre when you think about it. Sure, people knew the song at the weddings and all the rest of it, but to think that would then mutate into complete strangers saying to me 'Oho, Francie Brady, I'll chop you up.' People are always shoutin' across the street to me 'Leave Mrs Nugent alone, ya f**ker', and all this stuff.

It's kind of brilliant in a way. I just can't explain it. Maybe it just hit at the right time when Ireland was about to change. At just that moment maybe when things were changing from traditionalism to modernism, maybe there was a new bunch of kids that got a postmodern kick out of something that was old as well." McCabe confesses that he is surprised by the mythic weight the story carries for people, particularly because it was an unintentional by-product of the writing.

It seems that now he is deep in the darkest, most overtly terrifying period of his craft. A period that seems to have started with his latest novel, Winterwood, and that now finds expression in a play with chilling references to Ian Brady and Myra Hindley. He admits that he is fascinated by the idea of the "moorlands of the soul", and he refers to one of the pre-occupations that seems to be a subtle driving force in his work, a melancholic sense of mortality and loss:

"As you get older, you tend to look at these things in a starker light, because a lot of your people are gone." This unflinching ability to look at life's darker lessons head on seems to have come with age, and now allows him to look at Francie Brady in a "damnable" light because, as he says, "that's the colour of it. I think when I was a younger man I used to avoid these things, because I think when you're younger you have a resource of indomitable optimism, but you do not necessarily have that when you're older because the evidence is stacking up to the contrary. So I was thinking this is quite possible what will happen to Francie Brady, that all his demons come back on him, and that voice that damns him at the end is actually his own."

Comic sensibility But it's not all doom and gloom.

This, after all, is a writer with a fine comic sensibility. A man who keeps a Dalek in his garage: "I was going to make a cocktail bar out of him, but I can't get him in the door because the bottom of him is too wide. I'm going to have to hack it off." For a moment I have an image of crazed Pat McCabe taking an axe to a Dalek, Francie Brady style. I remind him of the night I saw him give his first reading of The Dead School, and it brings to mind all the things he despises about public readings: "I do not know how anybody would get any enjoyment out of drinking cheap wine in a paper cup at 6.30 on a Wednesday. I don't know where that idea comes from. And every one of the staff are fed up that they have to stay behind. It's horrible!"

His own approach to reading is unique and ever evolving. He now has the Radio Butty show and a band called the Toblerones who punctuate proceedings with the Safe Cross Code jingle. He calls it "modern folklore". This need for something different started with readings involving Jack L and moved on to a collaboration with Gavin Friday on Emerald Germs of Ireland. Now Gavin Friday has written the music for The Revenant. " I like working with Gavin a lot. He's very old fashioned in some ways, like I am. He's very interested in Catholicism, although you wouldn't think it when he was running around Dublin dressed up in his mother's outfits. A lot of the influences that formed him formed me too, because we're not that different in age. It was a kind of a natural synthesis when we started working together."

There has always been something exhilarating about McCabe's work, whether in the headlong rush towards lunacy in the often ignored Dead School or the wild humorous extravagance of Mondo Desperado. He credits the "intoxicating" influence of director Sam Fuller for inspiring this energy, and remembers Fuller's sensationalist black-and-white B-movie, Shock Corridor. The film is punctuated by an unexpected burst of colour with the appearance of a waterfall: "And I remember thinking, 'I want to do that with words.'

Suddenly you've got a sudden burst of electricity running through it. All that kind of stuff I found exciting in language." For craftsmanship and linguistic courage he points to the influence of Joyce and the "disgracefully neglected" George Moore. Influences that have led him to his own unique style, and ultimately the lean pared-back horror of The Revenant.

McCabe himself is also balanced in his attitude to his novels, regardless of the occasional snide critical comment. "I'm not happy or unhappy with them. They're like your children, you would never say 'Oh she's a beautiful girl that sixteen year old, but the other one with the squint, we never let her into the house.'" McCabe is the antithesis of his unhinged protagonists and skewed fictions. He is intellectually fierce and uncompromising, and sure of his vocation, regretting the effect of all the "job-forlife bullshit of the seventies" which led him to leave the band he was playing with and become a teacher: "a kind of stupid idea really." Writing has always given him contentment: "there was always something missing that it provided".

At this point in his career he is philosophical about being critically mauled, and knows that urge to re-invent and challenge himself may have made him an easier target: "I suppose that happens if you're moving sideways as well as forwards. If you produce a book every so often that is clearly a wellcrafted literary novel of serious intent, well everybody's kind of happy in a way, because that's the way the machine is supposed to move. But if you're not built like that it sort of makes it awkward for journalists. At least if people are arguing whether you're a bollocks or a genius the work has some value."

As things stand, his work continues with its steady dark undertow, and its characters sometimes howling, sometimes laughing into a dark Nietzschean abyss. But if it's context you want McCabe is more than happy to provide it:

"Sometimes you go left for a play, sometimes you go right for a short story, but really you're all the time writing one long book that's chopped up into novels."

The Revenant runs at the Druid Theatre until July 26th as part of the Galway Arts Festival.