The flat door below heaved open, followed by the sound of someone labouring up the stairs.

‘You could probably get this for a hell of a good price now,’ panted Clive, as if he’d read my mind, ‘be a smashing first-time buy.’

‘Could you actually live here though? Every time you’d come up these stairs, you’d be thinking someone died here, horribly.’

‘I’d leave the blood and charge people for a look.’

‘Jesus.’

We both stared for a moment in silence at the spattered remnants of Marion Ryan’s final seconds, the red colour already browning.

‘What do you think then?’ said Clive.

‘Well, if I’ve learned anything over the past two years, it’s that crimes tend to be either personal or opportunistic,’ I replied. ‘This was definitely personal, wouldn’t you say?’

‘Well, if I’ve learned anything over the past twenty years, it’s to keep an open mind.’

I could feel his look. ‘Tell them what you think today, but don’t be too opinionated. They won’t respect that.’

I nodded.

‘You’re a PC, they’ll see you as nothing more than a street butler; present when needed, otherwise invisible. Know your place, son.’

‘Got it,’ I said, the words, ‘cannon fodder’ drifting through my mind.

I’d be fucked if I’d know my place in Clive’s class system. England, the world’s only courteous tyranny.

Marion lay on the waiting room table at Clapham police station, beaming and radiant. The photo of her and Peter on a recent night out dominated the Standard’s front page. Head tilted into Peter’s chest, her smiling blue eyes oozed contentment. Her hair – big and curly à la Julia Roberts’ in Pretty Woman – had an almost other-worldly crimson glow which seemed to drain all the blood from her milk-white skin. Her high cheekbones and freckled nose brought Eve to mind. But Marion’s features – nose, chin, eyebrows, forehead – were more pronounced: she was striking, rather than pretty. Juxtaposed with her strong face was a smile so coy, kind and natural that it lit up the page, casting a sad shadow across my chest. I forced my eyes away from the photo to the accompanying report. I needed to expunge all emotion, stick to the facts.

London-born of Irish parents, twenty-three-year-old Marion O’Leary met Peter Ryan in North London’s Archway Tavern when she was seventeen. Peter, from Mayo, had been her only boyfriend. They got married in Ireland last year.

I’d met lots of second-generation Irish in London, like Marion. Invariably, they held a romanticised view of ‘the old country’, usually based on a handful of childhood holidays, and family propaganda. Most had been indoctrinated in Irish culture since birth. I bet Marion attended the local Catholic school and church. She would have taken First Holy Communion and Irish dancing classes and celebrated Paddy’s Day more than I ever did.

She would have socialised in Irish pubs and clubs, hoping to meet a dashing Irishman who’d whisk her off her feet. They’d marry and move to a bungalow in the west of Ireland, where their kids – red-haired, freckled and plentiful – would run about barefoot and gleeful, stopping only to say the Angelus together at six o’clock each evening.

We first-generation Irish had news for these ‘plastic Paddies’, some quite old news at that: romantic Ireland’s dead and gone.

I couldn’t help assuming that Marion had bought wholesale into her parents’ dream. Marrying her first proper boyfriend made me suspect she was trusting, idealistic, a little naïve – not the type to have an affair, or to let a stranger into her flat. So how then did Peter fit into all of this? Why would he kill her? Maybe he was having an affair and couldn’t bring himself to tell her. After all, most Irishmen will do anything to avoid a scene. Or she confronted him about it and he flipped. But surely he didn’t hack his own wife to death on the stairs with a knife, then go back to work? That didn’t stack up.

I was mentally listing the most compelling reasons why this crime had to be domestic when I leapt at the sound of my own name. The uniformed officer led me out of the waiting room, down a long corridor, through a pair of electronic security doors, along another corridor, then left into an interview suite. I sat there in airless isolation for what seemed like an age, a hothouse mushroom incubating on stale smoke and sweat. I couldn’t understand why I felt so nervous.

Two middle-aged detectives finally strolled in, coffee cups full, fags on, fresh smoke sweetening the fusty air.

‘I’m DS Barratt, this is Inspector McStay,’ said the taller one, letting his superior sit first.

I talked through everything that happened last night, throwing in my theories for good measure. When I wrapped up, they told me to write it all down in a statement, minus the theories. As I wrote, I repeated my assertion that Marion must have known her killer.

‘Thank you, PC,’ snapped McStay, emphasising my job title, ‘the Big Dogs are all over it now.’

I went on, ‘She clearly let her killer in. She knew him or her well enough to pick up her post.’

‘Who would be your prime suspect then, Lynch?’ asked Barratt, mildly amused.

‘I’d have to start with the husband, Peter. Was he playing away? Did she find out? Has he got a history of violence? It doesn’t usually come out of the blue, does it? I’ve read about a lot of other cases and it normally escalates from domestic abuse. Peter is where I’d start.’

‘Good theory,’ said Barratt, scanning my statement, ‘we’re bringing him in as we speak. He’s going to talk to the press, appeal for help to find her killer.’

He looked up at me: ‘Alongside Mr and Mrs O’Leary, Marion’s mum and dad.’

I tried not to look confused.

McStay seized the moment: ‘Peter is staying with Marion’s parents. Do you think they’d have him living in their own home if they thought for one second he could have been capable of killing their daughter?’

He got up, strode to the door and flung it open: ‘Better get back out there, son. Those bike thieves won’t catch themselves.’

As I made my way back out of Clapham police station, I recognised the rodent-like scurrying of her majesty’s press.

Amid the yapping throng surged my brother Fintan, now Deputy Crime Correspondent of the London-based Sunday News. If the Chief Crime Correspondent didn’t have a pension plan, he needed to get one, soon.

I followed the hordes into a large conference room, taking a seat near the exit. I wanted to see Peter explain himself. I wanted to see if his in-laws exhibited any kind of suspicion.

Within seconds, my identity had become a talking point among a group of photographers. Fintan joined their chat, clocked me and scuttled over, beaming.

‘I hear you found the body?’ he roared, confirming he’d no shame.

‘Jesus, would you not have some decorum, Fintan.’

‘Maybe we can help each other.’

‘I’m not talking to you.’

‘Come on, Donal.’

‘You know I can’t tell you anything.’

‘Fine. Fine. I wonder though, is a PC like you supposed to be nosing around a cordoned-off crime scene after the case has been taken over by a senior detective?’

A red warning light pinged on in my brain.

‘Well I am a police officer, Fintan. That’s pretty much what I do these days.’

‘Oh okay. It’s just … ah nothing, doesn’t matter.’

‘What?’

‘Well, you see that guy over there?’ he said, pointing to a large man cradling a cannon-sized Canon camera.

‘He’s a snapper, from the Standard.’

‘Bully for him.’

‘He said he took your photo earlier today, as you came out of the house on Sangora Road.’

My heart set off on a gallop.

‘And guess what? His editor likes it. Donal, you’re going to be on the front page of the Evening Standard. Imagine that! You on the front page? I’ll send a copy to Daddy. He’ll be made up.’