I believe that if my father had lived he might still enjoy wearing a fisherman’s cap. He never went to sea, but got a new cap every year on birthdays, so Hattie said. He liked looking at the brown Thames water from almost any of the bridges or wharfs along the river, and would always suggest an outing to such places for a Sunday walk. Hattie also remembered that when my father was a child he had described the river as a yawning snake, which to me seems precocious. To him, snakes meant danger, and the space below the bridges was filled with slithering horror. They found things in rivers too. It said so on the news. Whatever people secreted in the unfathomable water eventually washed up.

Sometimes when I drink a cup of tea I think of him. This doesn’t ever happen with coffee. I imagine him tiny, legs over the rim of a mug, ready to fall.

In the inter-war years it seems most likely that my father attended what was known as a higher grade or higher elementary school, probably on the Isle of Dogs. Even after some internet research, these general terms for schools, never mind the names of individual schools or locations, remain unclear. My son has told me you can find anything on the internet. He is wrong.

It’s probable that my father took lessons intermittently at best. What is clear is that he developed an interest in photography during his teenage years, having somehow come into the possession of a Voigtländer folding camera. I know this because I have a few faded pictures, dated and annotated in what is presumably his own hand. On each, the word Voigtländer appears, along with the exposure settings. According to Hattie – oh Hattie! – there were many more of these photographs, but somewhere between moves from the East End to Islington they were lost, as was much else.

Hattie said that many of my father’s old pictures were of workers at Millwall’s docks. She described the docks “impounded water”. The idea of locking up a river sounded unnatural and unwise. My father had taken pictures of men holding up their union cards at call-on; of sailmakers and lightermen, tally clerks, wharfingers and gangs of stevedores. There were pictures that might have been taken from aboard the free ferry at Woolwich and imported goods that are now unthinkable – live elephants, piles of ivory and snake skins twice the size of a man. There were also images of what remained of the wild Plaistow Marshes, which stretched from Canning Town to Barking Creek. I have none of these photos though. I would love to have seen them. When Hattie talked of them, in her last years, the descriptions fell from her mouth lifelessly, as if she were describing any old pictures that she might have half recalled from a picture book or a newspaper. I sometimes wonder whether they existed at all.

The few photos I do have from my father’s collection show a keen interest in the barges that were once a much more common sight on the Thames. The names can just be made out on a few: Lady Daphne, Cambria, Victor, Wyvenhoe. There are a few other fishing boats too: the oyster smack Boadicea; a Humber keel with its already hazy name made more illegible by what is perhaps a coffee stain; an eel barge near the Dutch Mooring at Billingsgate; and two Thames Estuary fishing smacks, Primrose and Perigee.

Did my father drink coffee? Perhaps he drank that Camp coffee that we used to have – the stuff in the dusty bottle that left a sticky ring in the dark back of the pantry cupboard. I wonder. That shelf that was too high for any young child to reach (so there’s where the wells of your imagination take you!). And there’s my mug of tea. And there’s my father growing ever smaller on the lip of a precipice, slipping down and away into the dregs of something gone cold.

I learned that the Thames Estuary smack Perigee sailed between St Katherine’s Docks (which in the 1930s still handled cargoes of luxury goods including sugar, rum, spices and perfumes) and Rochester, Ipswich, Hull, Newcastle – even northern France. I’ve imagined this small boat in rough Channel seas, or mooring up under the Tyne Bridge and unloading tales of The Mudchute and Deptford in a clash of accents and experience.

Perigee was built in the late 1860s by Frederick Wheeler in Maldon, Essex, and first registered for an oyster and herring fisherman, Samuel Wilson. It was re-registered in Brightlingsea, Essex, in the 1880s and then in Faversham, Kent, in the 1890s. From here, until its appearance in my father’s photograph, the details are murky. At some point in the 1930s it was fitted with an engine, thought to be adapted from one found in a Ford Model T. This wasn’t – maybe isn’t – unusual: the term for having undergone such an adaptation is “marinised”.

Perigee makes an appearance in the London Fisheries Register of 1936. It is listed as being owned by Thomas Culshaw of Rotherhithe, who was well known in the area at the time. Born into a family of fishermen (who were originally from Margate and had arrived in London almost accidentally), Captain Tom was easily recognisable by his “moon-like visage”. No record I can find tells whether that means a face as round as a full moon or as lop-sided as a crescent one. In his youth he had apparently sailed to Cape Verde, Easter Island and Brazil. He was a renowned smoker of a calabash pipe stuffed with expensive Turkish “Joy Smoke” tobacco, and entertained crew with his nimble playing of the spoons and perhaps also the melodeon. He had a spaniel, Mr Tipps, who accompanied him everywhere. It looks most likely that Tom Culshaw was killed during the war, sunk in his boat off Potton Island near Foulness – “lost through enemy action”. The name Perigee disappears from the London Fisheries Register in 1943 and never returns. What became of Mr Pitts is unknown.

I have been researching my father’s early life, off and on, for the past few years. It’s an unsteady project. Sometimes, you could say, I take a sip of it, sometimes I drink deep. You can delve down into a history until it’s dark and you’re wanting air, and you’re trying to get back up – up to the surface.

I wonder what happened next. For the docks and dockers of the Isle of Dogs and beyond, World War Two is a barrage and blaze of all the words that for some people at the time must have become horrifically familiar: Black Saturday, the Gothenberg, ARPs, Mulberry harbours, South Halsville school, Beckton gasworks, UXBs, first-aid posts, Kearly and Tonge, trains to Weston-super-Mare and Somerset, safe camps in Epping Forest. I’ve looked for my father’s name but he’s nowhere in it. It’s all craters and smoke. Hattie would roll her eyes and light a Regal. I draw blanks. I put the kettle on.

He reappears as a gaunt man in a photograph from the late 1940s, sitting atop a pile of pristine bricks, the highest up in the picture of six men, all young, grinning and gurning at the camera. One is toothless, two wear braces, one has a belt around his high-waisted trousers. Shirts are unbuttoned and sleeves are rolled up. My father is wearing his fisherman’s cap, others wear flat caps and one appears to be sporting a knotted handkerchief on his head. The only evidence of work-wear is that each man has a protective leather pad strapped to his shoulders. In the background are a giant crane and the hull of a ship. Everything is grey, fading to brown. It is the only picture I have of him. I have looked at it so long I can conjure the image whenever I want. And I have looked at it so long it tells me nothing at all.

He should have stayed for me.

Hattie wouldn’t tell me any more. She preferred talking about him as a child, her baby son. My mother told me nothing, bless her. He was off bounds. I didn’t know anything about him for years. Lots of us had fathers who were lost, so it wasn’t unusual. I just thought mine was lost for the same reason. In fact, he left my mother shortly after I was born. Of course I don’t remember. He slipped through the rubble of London’s East End and never reappeared, at least not to us. I found out later there were reports he had taken his life: jumped off a bridge or some jetty at one of the wharfs. My father couldn’t swim.

I now consider it strange that the only image I have of him is one in which he’s sitting on top of a pile of bricks. There’s nothing solid about him at all. He spent most of his life at the water’s edge and finally fell into it. He still falls through my hands every day. He floats off. The world turns. I orbit him silently. The tide rises again. The water is deepest when the moon is closest. The more I reach out the more he recedes into a history that’s always flowing away, even as it grows: incessant, spiteful, cowardly. His secrets are gone. The river washed up no body.

Iain stared glumly across the stained formica.

“It’s like I was telling the sculptor Rachel Whiteread, Will, when I was explaining to her how Hackney’s pre-Games decontamination and realignment into a fugitive cartography of designer lock-ups and guerrilla sofa bars had created a hallucinatory Ballardian nexus of dystopian interzones and put me right off the idea of getting a cat – some of the ley lines they dug up to build the Basketball Arena had been there since the days of King Lud.” He paused. “Look, I drew her a map.”

Iain passed Will a piece of paper. It was a menu from a Turkish cafe in Dalston, covered in biro scrawl and with a small piece of what looked like chargrilled aubergine stuck to one corner. Will pulled a face.

“Are those conduplicated testicular orbs with an intermedial indurated intromittent organ extravasating prostatic fluid?”

“A spunking cock and balls? Yes. I think she must have drawn them when I wasn’t looking. There are more all over the back, look. I think she gets a bit frustrated, just filling the negative spaces inside objects with concrete in order to make people think twice about things.”

“Hmmm,” said Will, slipping the menu into his pocket. “So, tell me: what tactical methodology do you advocate that we implement as a counterpoising praxis?”

“What do I think we should do about it? Well, I suppose we could try walking around something. Like the M25, or the Olympic Pa…”

“Can you execute an intramental reinstauration of the inimical predicament that eventuated when you essayed an experimental circumambulation of Peter Ackroyd?”

“Do I remember what happened when I tried to walk round Peter Ackroyd? Of course I do.” Iain paused. “He didn’t like it, did he?”

“He articulated his grievances to the constabulatory functionaries.”

“He called the police, yes. But it was taking much longer than I’d anticipated.” Iain leant forwards, dropped his voice to a whisper, and gripped the plastic ketchup bottle on the table in front of him with both hands. “I actually wondered afterwards whether – ” he slowly rotated the rotund red receptacle between his palms – “he might have been turning round.”

Will gazed out through the steamy, net-curtained window.

“I suppose,” he said at last, “we just have to accept that it was all a lot of fun, and most people enjoyed it.”

Iain stared at him.

“I’m sorry,” he said, “I’m not sure I understand what you mean.”

The pickaxe scrapes and drags. Iron grates on rock, scratches, chimes on stone. But, even so, Steve can still hear some smug pillock yabbering on the radio.

“… back in Roman times, I think you’ll find, the River Walbrook was London’s waterway of choice…”

“Think you’ll find?” Steve snarls, stopping work to heckle. “How exactly? In a tardis?”

He laughs at the quickness of his wit, but there’s no one else here to appreciate it and his mood soon sours as this tosser bangs on about London’s lost rivers. Where on earth do they find these morons, he wonders. The pick lands heavily, chips of Victorian cement spurt up from the floor. Is there a talent agency for know-alls somewhere in Soho? Somewhere that TV and radio people call when they need a saddo to talk about some weird obsession?

If Shelly were here she’d say something about anger issues – that Steve has them – which would wind him up even more. But she isn’t here and he doesn’t want to think about her psychobabble; he just wants to get on with the task at hand. This was her idea after all. If she’s going to live here, they’re going to need more space, that’s what she said. And it’s a lot cheaper to extend than to move. She’s right about that. Who can afford property in London these days? Russian mafia and Saudi princes, that’s all. And why move when all the cellar needs is a little more ceiling height? Shelly wants to do it up in purples and pinks, fill it with shag-pile rugs, beanbags and candles. She says it will be their secret love nest. She’s buying a lava lamp at the weekend. Yes, he can see it now: the two of them lying on a thick rug, naked in the candlelight, entwined in each other’s arms.

Steve scrapes faster, hoping that the rasp of iron against stone might drown out that prat’s nasal twang and the deejay’s false laughter. He doesn’t know why he listens to LBC, except that it’s something to shout at and it breaks the tedium of working down here, alone in the cellar.

“… yes, and the River Effra has always been a feisty one, if I may put it like that – flooded and carried off Sunday roasts from houses circa 1914…”

Steve wrinkles up his nose and mimics squeakily, “circa 1914”. His sarcastic oo-oo-sound ricochets round the damp stone walls of the cellar as perspiration runs down his forehead. He pauses to mop his face on his sleeve and crouches to measure his progress. The Victorian grout is loose now, chipping and curling up so that soon he’ll be able to wedge the pick between the flagstones and lever the first one off the ground.

“… a coffin, from West Norwood Cemetery, no less, was carried under south London all the way to the Thames…”

No less? No less? Did that mammoth arsehole really say West Norwood Cemetery, no less? Steve can think of more glamorous venues. He laughs to himself as he imagines taking Shelly to the cemetery for a romantic evening out. Not that he would of course, it wouldn’t be worth the aggro, but he can indulge in fantasy, can’t he?

He leans on the handle of his pickaxe and swigs some water. This is hard work but it’ll be worth it. At least, he hopes it will.

Now that he stops to think about it, he likes the brickwork as it is. Seems a shame to cover it up with girly pink. And it might be a bit too cold to get completely naked down here – there’s no heating and it’s damp. Steve readjusts the picture in his head: making love with his socks on; Shelly in that awful teddy-bear onesie she wears; the drone of a fan heater in the background; the cold from the floor seeping up through the shag-pile rug. Truth is, as love nests go, this one won’t be very cosy.

They don’t need a love nest anyway. There’s a perfectly good bedroom, isn’t there? What this room would be really good for is the Xbox. Steve could play computer games all night down here – lose track of time, absorb himself in the worlds of Grand Theft Auto and Skyrim, with the volume up as high as he likes because he wouldn’t be disturbing anyone. All he has to do is persuade Shelly to see things his way before she goes out and buys the bloody lava lamp.

Next day, and the radio is rattling on with a big row about strikes on the Underground. Underground rivers. Underground trains. So much of London’s life is underground, Steve wonders why more people don’t extend into their cellars. Except that it’s hard work levering up flagstones that have been in place for more than a hundred years. They’re heavy to drag across the cellar in the dark too. And he wonders whether it’s worth the trouble now that Shelly’s in a mood with him.

“Oh shut up!” Steve shouts at some miserable moaning commuter.

He should never have mentioned the Xbox, should have known that would upset her. She called him selfish, and trotted out her usual line about him never listening. He can still hear it now: Trouble with you Steve is you never listen… blah-blah-blah-blah-blah.

He decides not to dwell on it, to think about other things instead, and eases up another flagstone, which he props against the wall and marks with chalk. He’ll finish pulling them up today and tomorrow he’ll dig. He only needs to go down a couple of feet. Then he’ll put the flagstones back as they were, like pieces in a jigsaw, like London Bridge when they moved it to America.

Underground car parks, there’s another one.

He loses track of time, pulling up flagstones and wheeling them across the blue-grey clay to the wall. He doesn’t stop until he’s upended each stone, then he gazes at the soft new floor he’s uncovered. It seems to sweat under his feet. Underground sweat, he thinks. A trick of the light, maybe, the way it glistens, or a mirage.

He’s knackered. He’s seeing things.

Steve dreams of King Canute, sailing through Brixton on a Viking longboat, gliding past the Ritzy yelling in a smug nasal twang, “Oy, Steve! Thought you were getting a Waitrose round here?” He watches Canute’s ship disappear up Effra Road towards his flat. There’s Shelly, all dressed up on the back of the longboat. She smirks at Steve as if to say she’s too good for him now. King Canute puts his arm round her and shouts something else, but he can’t hear it.

He wakes with aching muscles, makes coffee and takes it down to the cellar, where he flicks on the radio, lines up his buckets and starts to dig. He could have sworn the floor was grey yesterday – a pleasant blue-grey somewhere between Wedgewood and gunmetal. Now it’s caramel and clammy to the touch. But what does it matter? He’s only going to dig it up, put it in buckets and haul it up to the garden. He wiggles the spade into the clay as people phone LBC to argue about Thames Water and hosepipe bans. The clay sticks to itself, gloops and squelches as he cuts it out of the cellar floor and lifts it into buckets.

By the lunchtime news he’s cut a trench two feet deep that’s broad enough for him to stand in. He knocks back the water in his bottle, listening to the mayor go on about London Underground workers. “You plonker!” Steve shouts at the radio.

London’s mayor. Now there’s a man who never listens, but Shelly won’t hear a word against him, oh no. Thinks he’s funny with his floppy hair. Steve jabs his spade at the clay beneath him.

Now that he comes to think about it, Shelly’s got a nerve telling him he doesn’t listen when every time he sees her he has to put up with her prattling on about her fitness regime or getting in touch with her spiritual side. Clay slides off his spade into a bucket. He stabs at the floor again. He’d like to see the how the mayor would cope with Shelly blabbing on. Or King Canute for that matter. All this work he’s doing! All this effort! For what?

Steve pauses, glances round the cellar and fast forwards: purple shag-pile carpets, purple lava lamp, the sweet pong of lavender candles and the sound of Shelly’s voice as she sits there in her teddy-bear onesie, dissecting their relationship, telling him he has issues. And him, listening – having to listen to all this, every day, till the end of his natural life.

No, he can’t do it. He’s going to have to tell her, isn’t he? That she can’t move in. It’s over. They’re not right for each other. God knows how but better to do it before she brings her stuff round, before it’s too late. He licks the brine from his lips, hears it squelch under his arms and feels its warmth between his toes. Shit. How’s he going to tell her? Best get it over with. Tell her straight away. Yes. Now. Why prolong the agony?

He throws down the spade and starts to climb out of the trench. Only he can’t; it won’t let him go. Sodden clay grasps at his feet and clings to his boots. It weighs down his legs. Sweat runs off his forehead into his eyes, oozes from his skin and dampens his clothes. Water laps at his ankles. He’s standing in a puddle, but it feels like he’s sinking, being sucked down through the hole he’s dug.

On the radio, the mayor has moved onto water cannon.

“You utter prick!” shouts Steve.

He’s up to his waist in water now, arms flailing round for something to grip onto. He tries grabbing one of the buckets, but it tips – the clay inside sluggish as it rolls towards him. He snatches at the floor of the cellar, but it slides down the bank of the trench with him, splashes into the water that’s rising up to his chest, his Adam’s apple, his chin.

The mayor claims most Londoners support the use of water cannon in limited circumstances, which pisses Steve off but there’s nothing he can do about it now. He can’t even shout at him. Not any more. Water is seeping up his nose. He spews and spits but the taste of wet clay sloshes inside his mouth. Grit scours the inside of his cheeks. Underground rivers, he thinks as he slips below the surface. He closes his eyes and sees Canute on the back of the longboat, shouting at him: “The River Effra has always been a feisty one!”

His eyes ping open and he watches as his last breath floats away in bubbles that gently pop on the surface, one by one. He should have listened. Perhaps Shelly was right, but it’s too late now. He sinks through the mud to the river below, and is carried underground to the Thames.