Our local library was like something out of Germany, that’s what everyone used to say; and that summer when I was twelve, and I had started to find the macabre in everything, I looked at the library’s witchy cupola and steep pitched Bavarian red-tiled roof and I thought of eagles’ nests and wolves’ lairs and mass murder. It had only a small range of books—it was a bulky building; so bulky its insides seemed squeezed—and too many of the books were fiction, which I had no interest in. Still more were about nursing, strangely, and gardening and car maintenance—something for every contented resident of the district of Foxrock and Cabinteely. And then I found something for me: ‘Omits absolutely none of the gruesome details,’ the cover promised. It was The Complete Jack the Ripper by Donald Rumbelow, and I was to take it out on repeat loan for the next few months. The facts of the case were easy to memorise because I was so quickly engrossed. I learnt all about the process of the investigation, the dramatis personae, and, of course, the ‘gruesome details’. Then I became enraptured by the fable that contaminates the history, the kind of stuff that infuriates serious students of the Jack the Ripper case: the legend of the doctor in the top hat with the Gladstone bag; wacky conspiracy theories involving Lewis Carroll, the Elephant Man, the Duke of Clarence, and the Freemasons. I was enraptured by it all, the setting most especially. London, the most mythologised of cities, had this whole other mythos weaved of its lines. I couldn’t get there quickly enough, and even before I did, I felt that I understood it well. Geography— both the serious students and the conspiracy theorists agreed—was key to the Ripper case. Plotting the murder sites on a map, and the possible routes between them, brought one closer to the mind of the killer, they said: by narrowing the range of the fiend’s likely home ground (the historians), or by marking the coordinates of a pentagram or some other occult symbol (the crazies). My approach was vaguer than that, if nearer in its intent to the crazies’: I used to pore over the London A to Z street atlas in a daze, or a trance even, willing an invisible plumb line from my subconscious to stir. I would try, God love me, to psychically experience those streets, to divine from the shape of the clusters and rookeries that they formed, and even from the typographies that labelled them, what their personalities were. I noted that the names of the tiniest streets—the courts and passages—were written in a strange, tentative, almost handwritten text. One such was Mitre Square, where wretched Catherine Eddowes was torn to a shambles. It had exactly the same typeface as used in the late-Victorian Illustrated Police News.

I first went to London when I was seventeen, with my uncle. He’s a bachelor, and still lives in the house where he grew up with his parents and my father. His mother (my grandmother) had been born in 1904 in Manchester—within sixteen years of the Ripper murders, and only a few hundred miles from where they took place. I so badly wanted to find in that house—in the attic, say, or a locked desk—a vital piece of evidence relating to the Ripper case, and strongly believed that one day I would. I remember my excitement in those dawn hours the morning of our departure to London. I thought of the streets I would finally walk, on the trail of a cast list that read like a census of Punch caricatures: John Pizer, Elizabeth Stride, Israel Schwartz, Frederick Abberline, PC Mizen, Polly Nichols, Martha Tabram. My itinerary would of course take in the canonical murder sites: Buck’s Row (now Durward Street), Hanbury Street, Berner Street (now Henriques Street), Mitre Square, Miller’s Court (now razed). And then there were the ancillary sites: the side alleys, the escape routes, the track of a bobby’s beat. Goulston Street, by its very name, evoked the appeal, for many, to this case: the glamour of grisly death. Here the killer may or may not have left behind his handwriting in the graffito ‘THE JUWES ARE THE MEN THAT WILL NOT BE BLAMED FOR NOTHING’. Below the daubing was found a bloodied rag, a swatch of Catherine Eddowes’s apron. Most agree it was taken by Jack to clean his knife. Some suggest it was used by the penniless prostitute as a sanitary cloth.

My uncle’s house was like an anteroom, an acclimatisation bell, ahead of our visit to Victorian London. It hadn’t changed much in seventy years. The décor remained exactly as my grandparents had set it out, and all the ornaments they’d gathered over time—snow globes from San Giovanni, a holy water bottle from the Marian Year of 1954, a letter opener from the Eucharistic Congress year of 1932—sat on the shelves and mantelpiece where they’d first been placed. And it stank of tea: loose-leaf tea, over-stewed, furred on the crockery, soaked into the carpet. In the kitchen, a frayed rag, indelibly stained, hung undisturbed: one corner jammed in the criss-cross slit of a rubber tea-towel holder.

(When I think back to that time—the time I first became interested in Jack the Ripper—I feel a catch in my throat, and I could retch. Rumbelow tells a story of a knife, complete with blood-streaked, blue-velvet-lined leather case, gifted to a woman, in 1888, by a policeman who had kept it after a raid on the home of a Ripper suspect; the knife was then passed down a couple of generations to another woman who used it as a kitchen carving knife. I can remember how my appetite was spoiled after reading that anecdote: how chicken fat started to feel against my uvula—grainy and thick; and how chicken skin seemed chewier; and I remember the bittiness of cartilage, the sudden yield of grizzle, fragmenting between my teeth.)

Donald Rumbelow himself was the guide on our walking tour of Jack’s London. I was glad of his authority, as much, as for anything else, because Spitalfields at night was a spooky place. Having travelled across London from Covent Garden to the City and then into the East End, we had left behind bright lights and clinking glasses and entered a dead zone. Deserted streets of office blocks suddenly gave way to deserted streets of tall weavers’ houses and warehouses, empty and blackened like rotten teeth. The East End, as recently as the mid-nineties, still felt like the shadowy back end of the City on the Hill, an extramural slum, and it wasn’t a place I would have liked to linger in on my own. There was a feeling of hostility and suspicion: not just in my imagination, I’m sure—but in the air. Locals seemed weary, at best, of the nightly parade of tourists through their quiet neighbourhood. On Hanbury Street, opposite the site of Annie Chapman’s murder, an angry Bangladeshi man shouted down at us from a top-floor window of one of those whittled Huguenot homes. Rumbelow was unflappable, or perhaps just inured to abuse. He told us he had been a bobby in the last days of gaslight. I could imagine him disappearing into a peasouper with his whale-oil lamp.

We followed him to The Ten Bells, where he left us. In the 1880s the pub had been a meeting point and shelter for prostitutes. Glass cabinets now served as display cases for Ripper merchandise, and a wooden panel on the wall was even painted with the names of Jack’s victims, like a roll of honour in a servicemen’s club. It was all a little tacky but, nonetheless, in the dim amber light, in among the darkened wooden fittings and the misty mirrored glass, it was possible to imagine you were in the company of costermongers and seamstresses. It wasn’t long before we were mellow on sweet English ale and had ceased to worry about finding a way to Aldgate East tube station and the safety of the West End.

I had a camera with me; at one stage the door to the cellar was left open, and I ventured to take a quick snap of the stairs leading down. The following week I got the reel of film developed, and—I’m not joking—there was a large smoky blob hovering in the middle of the picture.

A couple of years later I came again to The Ten Bells, with a girlfriend. In daylight, Spitalfields seemed even more depressed and shabby. It was a grey day, and the wind busted through Whitechapel High Street, west to east, rippling the surface water. We turned up Commercial Street, clinging to each other, eyes on the wet pavement, thoughts on that warming ruby ale. My girlfriend remarked that there seemed to be a lot of hookers about. It was true. Women who were patently sex workers—tottering on the tightrope of the kerb and dressed as if the sun, rather than the rain, was beating down—commanded the largely empty street. It didn’t surprise me to see; I’d read that Commercial Street was still a haunt for prostitutes. Even so, I somehow didn’t expect the trade to be so openly flaunted, so commonplace. In 1888, accounts speak of this street teeming with prostitutes, at all times of day, and in all weathers. We could have been seeing those very same people, trapped in a zoetrope of perpetual motion; one of the boasts of the East End was that it was the authentic London, where a way of life remained unchanged for centuries. But this—seeing these prostitutes, walking the same ground as the victims of a sexual psychopath over a hundred years earlier—felt surreal rather than real. It made me queasy about my interest in Jack the Ripper.

The lee of The Ten Bells offered some shelter from the rain, which we were thankful for, as the doors of the pub were locked. I looked about me, down the street, and then over at Christ Church Spitalfields across Fournier Street. Another Ripper landmark: this was a sort of sex-trade maypole in Victorian times, a pile around which the most desperate women of East London, dragging the ragged hems of their skirts through the rain and horse shit, performed a charade of peak-fertility for the price of a night’s lodgings or cup of gin. The building was the work of Nicholas Hawksmoor, the second-most famous church-builder in London after Wren and easily the most notorious. His devotion was said to be to the occult rather than to Christianity, and a dark mythology had grown up around him and his buildings. Naturally, this mythology had become interlaced with that of the Ripper’s. It was an irresistible association: writers as respected as Iain Sinclair and Peter Ackroyd had written about the pulse of Hawksmoor’s satanic beacons and their significance to the Whitechapel killings. Alan Moore, in his graphic novel From Hell, described Christ Church as the architect’s ‘creed of terror and magnificence most forcefully expressed… Its tyranny of line enslaves the nearby streets, for ever in its shade.’ I thought he was seeing far too much in all this. To me, Christ Church was a beautiful and well-proportioned eighteenth-century building. I was put in mind of some of Moore’s other outlandish theories; for example, he dates Adolf Hitler’s conception to the exact moment of one or other of the Ripper killings, as though there’s only so much evil to go around, as though evil is something at all.

‘Here,’ said my girlfriend. She was peering through the porthole of her hands into The Ten Bells. I had a peek too; through the window I could see men, and only men, sitting on stools and chairs and all facing the same way. It wasn’t obvious what they were looking at, or waiting for. Most of them were wearing builders’ or tradesmen’s outfits, but a good proportion, in shirts and ties, had presumably made the short journey over from Bishopsgate or other parts of the City. A member of staff—the landlord maybe—clapped his hands, and this seemed to quiet the crowd, or focus their attention: on the cellar entrance, I could see now. This same man opened the door—his face bisected by a smile and his cheeks all Toby-jug ruddy—and from below the ground a young dark-haired woman—also smiling—smoothly surfaced; head first, then bare shoulders, then barely covered chest, then barely covered loins. My girlfriend and I watched on, deeply amused. Then there was another movement—a typically burly and sallow Saxon—and we were roused to back away, and then to run.

For years and years I found myself going back and forth between Dublin and London; sometimes just to catch an Arsenal match, sometimes to crash on my brother’s couch in Balham or Streatham or Tooting for extended stays. Usually, but not always, I tried to do something Ripper-related. One time I travelled out to the south bank of the Thames opposite Chiswick, where I wanted to see for myself a place called Thorneycroft’s Torpedo Works. Near here, in December 1888, a month after a young Irish prostitute, Mary Kelly, was hacked to shreds in her rented room, the bloated body of one the main Ripper suspects, Montague Druitt, was found floating in the water. The coroner estimated his body had been in the river for a month; coincidentally or not, not another murder was subsequently committed, and Kelly would achieve immortality of sorts as the last canonical Ripper victim.

I don’t know what I had come to see. Thorneycroft’s would have been at the opposite bank of the Thames and, in any case, might not have been identifiable. In the event, I could see nothing, on that far bank, that was obviously a torpedo works. But what was I expecting? A hole in the side of a concrete bunker out of which might have slid a metal cigar? Did torpedoes even exist in 1888? Well they must have: that’s how Thorneycroft’s was described in 1888—a torpedo works. This was one of the bleakest places I had ever been to. The Thames was low in its trough and for yards from each bank flats of silt reached to the waterline. Distant mudlarkers—licensed scavengers—sifted the slime for coins and bones. This place, this point on the river, more or less marked the gateway to central London. On the right, all was densely grey and honey-coloured. To the left, it was mainly green. Or, at least, it might have been, would have been, only it was winter, and so it too was grey.

My interest in the story of Jack the Ripper ebbed and flowed over the years, often in accordance with how embarrassed or guilty I felt about being interested in such a macabre thing. In the last ten years it has mainly ebbed. But then the last time I studied the case it was never more intense. That was in 2010. I was meant to be pushing on with a novel that summer, but I found ample distraction in the World Cup, and then—although I can’t remember what led me to discover it—I found a cache of podcasts online that analysed the Ripper case in the minutest detail. Each episode was at least an hour long, and there must have been about sixty of them. I became addicted. I wasn’t happy just to snatch a few minutes of a podcast here and there; I had to listen to an episode right to the end, in one sitting, and somewhere quiet, where I could scrunch up my eyes and strain to concentrate on every esoteric piece of information. And once that was done, it wasn’t enough just to listen to one episode; I had to listen through until my day was filled while more pressing and important business was pushed to the side. I became obsessed, and I became frightened in a way I hadn’t felt since I was a small boy. I began to imagine that a Victorian prostitute was walking up and down the laneway behind my house. I became convinced of it. When I was a small boy I used to see the head of Saint Oliver Plunkett hover and revolve in my room, and now I felt, in a real way, the presence of this Victorian prostitute. At night I was too frightened to go downstairs to empty my bladder, and so I kept a wine bottle beside my bed that I could void myself into. One night I woke up and the woman was standing at the end of my bed. She was wearing a dark green velvet dress and her dirty blonde hair was tied up in a bun. All her features looked like they’d been chewed out of apple flesh, and a scabbed crucifix was scratched into her forehead. She clutched one hand in the other in a gesture of humility or perhaps entreaty, but then said, ‘You’d say anything but your prayers. Go on, give us a shag, love.’ I lobbed the wine bottle, half-filled with urine, at her, and it smashed against the wardrobe.

Night draws on the East End and it could be any age. The financial markets close, the City closes, and Whitechapel is cut adrift from the life of leisure-hour London, the other side of an empty square mile of glass. The shutters of boutique businesses come clattering down and the young clear off to the pubs and clubs of Shoreditch, Hoxton, Dalston and Clapton. There is something ominous about the air here, always, at this time. The side streets trail away in the murk. Dogs go mad in the yards of social housing. From somewhere a cry of ‘Murder!’ rings out. Or something like that. (‘Mother!’? ‘Muntered!’?) When the details of the visual world are obscured the imagination seeps to the fore; and when the imagination is geotagged to its surroundings, and aware of them in all of their dimensions—temporal as well as physical—the darkness outside and inside the head undergo a kind of osmotic transference.

Then day breaks again and new details emerge—things that look as though they have crystallised into being only that previous night. Every day now the inner East End seems radically newer than the day before. The rate of change the last decade has been as rapid as it was in the nineteenth century, the last time London was pumping with global credit. Now Spitalfields is truly integrated with the City, and not just a place for financiers to grab a cheap bagel or a lunchtime strip show, before pegging it back to their glass offices; now the offices run all the way up Commercial Street. Now the reeky defile of Hanbury Street is London’s hipster high street. Now Spitalfields Market and adjacent Brushfield Street—once putrid with the run-off of market day—is as chichi a shopping destination as anywhere on the King’s Road. Where at one time there were gaps in the streets, now there is the most gorgeously finished architectural infill. More and more of the Victorian grain disappears by the month; what remains is cleaned up, re-glazed, window frames toned down in fashionable greys, so as not to embarrass the swish new neighbours. This is a steampunk locale now; the past is encased, recast. From everywhere, long-legged butcher men stride in from another time: in billowy striped bloomers and felt shirts and braces, with gobbets of sauce and strings of pork in their bushy moustaches. A man in tweeds runs across the street with a growler of beer snuggled under his arm like a pig. Women’s hair is tied up high, backlit by the sun. All lines lead again to London. But all lines do not lead to now; now is no longer a fixed point but a moving dial across the fixed fascia of history. The Ripper has never felt closer at hand.