Cannon Street police station is just moments from where I work; I must have walked past it a thousand times or more and never noticed it. Never needed it. My headache hasn’t shifted, despite the painkillers I took this morning, and there’s an ache in my limbs that has nothing to do with a hangover. I’m coming down with something, and immediately I feel worse, not better, as though the acknowledgement alone gives the virus permission to settle.

My palms are clammy around the door handle, and I feel the irrational clutch of panic that law-abiding people feel when a police car drives past. Justin hasn’t put a foot wrong in years, but I remember that first phone call from the police with painful clarity.

I don’t know when Justin started stealing, but I do know that day he got nicked wasn’t his first time. You take something small, the first time, don’t you? A packet of sweets; a CD. You don’t take twenty-five packets of razor blades when you’re too young to shave. You don’t wear a coat with the lining carefully cut at the top, so contraband can be dropped neatly inside. Justin wouldn’t say a word about the others. Admitted the theft, but wouldn’t say who he was doing it for, what he’d have done with the razors. He got off with a caution, which he shrugged off as though it was a telling-off at school.

Matt was furious. ‘You’ll have that on your record for ever!’

‘Five years,’ I said, trying to remember what I’d been told in custody. ‘Then it’ll be spent and he’ll only have to declare it if asked directly by an employer.’ Melissa already knew, of course, just like she knew about the fights he used to get into, and the worry he caused me when I found a bag of grass in his room.

‘He’s a kid,’ I remember her saying, after pouring me a much-needed glass of wine. ‘He’ll grow out of it.’ And he did. Or he got better at not getting caught. Either way, the police haven’t knocked on our door since he turned nineteen. I think of him now, wearing one of Melissa’s smart aprons, making sandwiches and chatting to customers, and the image makes me smile.

The duty officer is sitting behind a glass barrier, like the type you see in the post office. He speaks through a gap big enough to pass through paperwork, or small bits of lost property.

‘Can I help you?’ he says, in such a way that it suggests helping me is the last thing he wants to do. My brain feels fuzzy behind my headache, and I grapple for the words.

‘I have some information about a murder.’

The duty officer looks mildly interested. ‘Go on.’

I push a newspaper cutting beneath the glass barrier. There’s a piece of hardened chewing gum squashed into the corner, where the counter meets the wall, and someone has coloured it in with blue biro. ‘This is a report in today’s London Gazette about a murder in Muswell Hill.’

He scans the opening paragraph, his lips moving slightly around the unspoken words. A radio crackles on the desk beside him. The details in the Gazette are scant. Tania Beckett was a teaching assistant at a primary school on Holloway Road. She took the Northern line from Archway to Highgate at around 3.30 p.m., then the 43 bus to Cranley Gardens. I was going to meet her off the bus, her boyfriend is quoted as saying, but it was raining and she said to stay inside. I’d do anything to turn back the clock. There’s a photo of him with his arm around Tania, and I can’t help but wonder if we’re looking into the eyes of a killer. That’s what they say, isn’t it? Most murder victims know their attacker.

I slide the second cutting under the barrier. ‘And this is an advert from yesterday’s Gazette.’ White spots dance in front of my eyes, and I blink rapidly to clear them. I bring my fingers to my forehead and feel them still burning as I take them away.

The desk officer looks from one piece of paper to the other. He has the poker face of someone who’s seen it all before, and I wonder if he’s going to tell me I’m imagining the resemblance; that the dark-haired girl with the crucifix around her neck isn’t twenty-five-year-old Tania Beckett.

But he doesn’t tell me that. Instead he picks up the phone and presses zero; pauses and holds my gaze while he waits for the operator to pick up. Then, without taking his eyes off me, he says, ‘Could you put me though to DI Rampello please?’

I text Graham to say I’ve come down with something and won’t be coming back to work. I sip tepid water and wait for someone to come and speak to me, resting my head against the cool wall.

‘I’m sorry,’ the desk officer says after an hour. He introduces himself as Derek, but it feels too familiar to use. ‘I don’t know what’s keeping him.’

‘Him’ is Detective Inspector Nick Rampello, coming to Cannon Street from what Derek referred to as ‘MIT’, before apologising for his use of jargon. ‘The Murder Investigation Team. That’s the unit tasked with looking into this young lady’s death.’

I can’t stop shaking. I keep staring at the two pictures of Tania and wondering what happened between her appearing in the Gazette, and lying strangled in the park in Muswell Hill.

Wondering if it’s my turn next.

It was my photo in the Gazette last Friday. I knew it the second I saw it; I should never have let myself be convinced otherwise. If I’d have gone to the police straight away, maybe it would have made a difference.

There has to be a connection. Tania Beckett was killed twenty-four hours after her advert appeared; Cathy Tanning had her keys stolen forty-eight hours after hers. It’s been five days since I saw my own photo; how long before something happens to me?

A man comes in to present his driving documents.

‘Such a waste of time,’ he says loudly, as the desk officer methodically fills out a form. ‘Yours and mine.’ He glances at me, as if in hope of finding a sympathiser, but I don’t respond and neither does Derek. He looks at the man’s driving licence and notes down details with a slowness I suspect might be deliberate. I decide I rather like Derek. When he has finished, the man slots the licence into his wallet.

‘Thank you so much,’ he says, in a voice thick with sarcasm. ‘This is exactly how I like to spend my lunch break.’

He’s replaced by a woman with a screaming toddler looking for directions, then an elderly man who has lost his wallet. ‘I had it at Bank,’ he says, ‘when I came out of the Tube. But somewhere between there and the river it …’ he looks around as though it might materialise in the police station, ‘… vanished.’ I shut my eyes and wish I was here on such a mundane mission; that I could walk out with nothing more than mild irritation on my mind.

Derek takes the man’s details, along with a description of the wallet, and I force myself to take deep breaths. I wish DI Rampello would hurry up.

The wallet man leaves, and another hour goes by, and finally Derek picks up the phone. ‘Are you on your way? Only she’s been waiting since lunchtime.’ He glances at me, his face inscrutable. ‘Right. Sure. I’ll tell her.’

‘He’s not coming, is he?’ I feel too ill to be cross at the wasted time. What would I have done instead? I wouldn’t have got any work done.

‘It seems he’s been waylaid by some urgent enquiries. As you can imagine, the incident room is very busy. He asked me to pass on his apologies and said he’ll be in touch. I’ll give him your number.’ He narrows his eyes at me. ‘You don’t look well, love.’

‘I’ll be okay,’ I say, but it’s far from the truth. I tell myself I’m not scared, just ill, but my hands are trembling as I find my phone and scroll through the contacts.

‘Are you anywhere near Cannon Street? I don’t feel well. I think I need to be at home.’

‘Stay where you are, Zo,’ Matt says, without hesitation, ‘I’ll come and get you.’

He tells me he’s just round the corner, but half an hour passes and it’s obvious that wasn’t the case; I think guiltily of the fares he’s missing out on while he makes a mercy dash for me. The door to the police station swings open, and to my embarrassment I feel tears rolling down my cheeks as I see his familiar face.

‘You here for your missus?’ Derek says. I don’t have the energy to correct him and Matt doesn’t bother. ‘Double strength Lemsip and a drop of whisky, that’s what she needs. Hope you feel better soon, love.’

Matt settles me in the cab, like I’m a paying customer, and turns the heating up full blast. I focus on my breathing, trying to stop the violent shaking that seizes my entire body.

‘When did you start feeling like this?’

‘This morning. I thought it was odd I had a hangover – I didn’t drink that much last night – then my headache got worse and I started feeling shaky.’

‘Flu.’ He diagnoses me without hesitation. Like most cabbies, Matt is an expert in everything. He watches me in the rear-view mirror, his eyes flicking between me and the road ahead. ‘What were you doing at the cop shop?’

‘There was a murder last night. In a park close to Cranley Gardens.’

‘Crouch End?’

‘Yes. She was strangled.’ I tell him about the London Gazette adverts; about my own photo, then seeing Tania Beckett.

‘Are you sure it’s the same woman?’

I nod, although he has his eyes trained on the road ahead. He sucks his teeth, then spins the steering wheel decisively to the left, cutting through one-way streets so narrow I could reach through my window and touch the brick walls as we pass.

‘Where are we going?’

‘Traffic’s a nightmare. What did the police say?’

I look out at the street, trying to get my bearings, but I’m not sure where we are. Children are walking home from school; some on their own, others still clutching their mothers’ hands.

‘They called the detective inspector in charge of the case, but he didn’t come.’

‘Figures.’

‘I’m scared, Matt.’

He doesn’t say anything. He never was any good at handling emotions.

‘If it really was my photo in the paper, then something’s going to happen to me. Something bad.’ My throat feels scratchy; a hard lump preventing me from swallowing.

‘Do the police think there’s a link between the adverts and this murder?’

Finally we emerge from the warren of tiny streets, and I see the South Circular. We’re nearly home. My eyes are stinging so badly it hurts to keep them open. I blink rapidly in an attempt to find some moisture.

‘The desk officer seemed to take me seriously,’ I say. I’m finding it hard to concentrate on what he’s saying. ‘But I don’t know if the detective inspector will. I haven’t told him about my photo yet – I didn’t have a chance.’

‘This is weird shit, Zo.’

‘You don’t have to tell me that. I thought I was going nuts when I saw the picture. I think Simon still thinks I am.’

Matt looks at me sharply. ‘He doesn’t believe you?’

I could kick myself. As if Matt needs any more ammunition against Simon.

‘He thinks there’s a rational explanation.’

‘What do you think?’

I don’t answer. I think I’m going to be murdered.

We pull up outside my house and I open my handbag.

‘Let me give you some money.’

‘You’re all right.’

‘You shouldn’t be out of pocket, Matt, it isn’t fair—’

‘I don’t want your money, Zo,’ he snaps. ‘Put it away.’ His tone softens. ‘Here, I’ll help you inside.’

‘I can manage.’ But as I stand up my knees start to buckle and he catches me before I fall.

‘Sure you can.’

He takes my key and opens the front door, then hesitates.

‘It’s okay,’ I say. ‘Simon’s at work.’ I’m too ill to feel disloyal. I hang my handbag and coat over the banister and let Matt help me up the stairs. He pauses at the top, unsure where my bedroom is, and I point to the door next to Katie’s. ‘I’ll be fine, now,’ I tell him, but he takes no notice, opening the door and keeping hold of my arm as we shuffle into the bedroom together.

He pulls down the duvet on the left side of the bed. The side I used to sleep on when we were married. Now it’s Simon’s things on the table to the left; his book, a spare pair of reading glasses, a leather tray for his watch and pocket change. If Matt notices he doesn’t say anything.

I crawl into bed, fully clothed.

Simon wakes me. It’s dark outside and he turns on the bedside light. ‘You’ve been asleep since I got home. Are you ill?’ He’s whispering, one hand clamped around my mobile phone. ‘There’s a police officer on the phone. What’s going on? Has something happened?’ I’m hot and sticky, and when I lift my head from the pillow it aches. I reach for the phone but Simon holds it away. ‘Why are the police calling you?’

‘I’ll explain later.’ My voice disappears halfway through the last word and I cough to wake it up. Simon hands me my mobile and sits on the bed. I’m still feverish, but I feel better for having slept.

‘Hello,’ I say. ‘This is Zoe Walker.’

‘Mrs Walker, this is DI Rampello from the North West Murder Investigation Team. I understand you wanted to speak to me.’ He sounds distracted. Bored or tired. Or both.

‘Yes,’ I say. ‘I’m at home now, if you’d like to come round.’ Simon opens his hands and mouths, ‘What’s happened?’

I shake my head at him, irritated by the interruption. The reception at home is bad and I don’t want to miss what DI Rampello is saying.

‘… probably all I need for now.’

‘Sorry, what did you say?’

‘You didn’t know Tania Beckett, I understand?’

‘No, but—’

‘So you don’t know if she was working as an escort, or running a sex chatline?’

‘No.’

‘Okay.’ He’s brisk; speaking fast as though I’m just one in a long list of calls he has to make tonight. ‘So Tania’s photo appeared in a chatline advert in the London Gazette yesterday, Monday sixteenth of November. Is that right?’

‘Yes.’

‘And you contacted us when you recognised her photo on the news this morning?’

‘Yes.’

‘That’s really helpful, thank you for your time.’

‘But don’t you want to speak to me? Take a statement?’

‘If we need anything else, we’ll be in touch.’ He puts the phone down while I’m still talking. Simon now looks more cross than confused.

‘Will you please tell me what’s happened?’

‘It’s the girl,’ I say. ‘The one who was murdered. The picture I showed you this morning.’

I ran upstairs this morning as soon as the news report finished, shaking Simon awake; my words falling over themselves.

‘What if it’s all to do with the adverts, Si?’ I said, my voice cracking. ‘What if someone’s putting in photos of women they’re going to murder, and I’m next?’

Simon pulled me into an awkward hug. ‘Sweetheart, don’t you think you might be overplaying this a bit? I read somewhere a hundred people are murdered in London every year. Every year! That’s – what? – about eight a month. I know it’s awful, but this has nothing to do with a free rag.’

‘I’m going to go to the police station at lunchtime,’ I told him. I could see he still thought I was being melodramatic.

‘Did the police take you seriously?’ he says now, sitting on the end of the bed. He squashes my toes and I pull my feet out of the way.

I shrug. ‘The man on the desk today was nice. But he called the detective inspector dealing with the case and he didn’t come, and now he says they’ve got all they need from me and they’ll call me if they want to speak to me again.’ Tears push their way out from the corners of my eyes. ‘But they don’t know about the other photos; about Cathy Tanning’s, about mine!’ I start to cry, unable to think straight with my head pounding.

‘Shhh.’ Simon strokes my hair and turns my pillow to find a cool bit for me to rest my cheek against. ‘Do you want me to call them back?’

‘I haven’t even got their number. He said it was the North West Murder Investigation Team.’

‘I’ll find it. Let me get you some painkillers and a glass of water, then I’ll give them a ring.’ He moves towards the door, then turns, as though he’s only just noticed something. ‘Why are you on my side of the bed?’

I press my face against the pillow so I don’t have to meet his gaze. ‘I must have moved around in my sleep,’ I mumble.

It’s the only thing we ever properly argue about.

‘Matt is Katie’s and Justin’s dad,’ I used to say. ‘You can’t expect me not to see him from time to time.’

Simon reluctantly conceded the point. ‘There’s no reason for him to come in the house though, is there? To sit in our lounge; drink coffee from our mugs?’

It was childish and irrational, but I didn’t want to lose Simon, and at the time it felt like a compromise.

‘Okay,’ I agreed. ‘He won’t come in the house.’

When I open my eyes again there’s a glass of water on my bedside table, next to a little foil packet of pills. I take two and get out of bed. My top is creased and my trousers are twisted: I get undressed and find a pair of thick cotton pyjamas, wrapping myself in a big cardigan.

It’s nine o’clock, and downstairs I find the remnants of what looks like beef casserole. My legs still feel wobbly, and my long sleep has left me drowsy. I go into the lounge and find Simon, Justin and Katie watching TV. No one’s talking, but it’s a comfortable silence, and I stand for a moment, watching my family. Katie sees me first.

‘Mum! Are you feeling better?’ She moves to make room on the sofa between her and Simon, and I sit down, exhausted by the effort of coming downstairs.

‘Not really. I’m totally wiped out.’ I haven’t felt this ill for years. My bones ache and my skin hurts to touch. There’s a stinging sensation at the back of my eyes that only goes away when I close my lids, and my throat is so sore it’s a struggle to talk. ‘I think I’ve got flu. Proper flu.’

‘Poor baby.’ Simon puts his arm round me and for once Katie doesn’t say anything about what she calls ‘public displays of affection’. Even Justin looks concerned.

‘Do you want a drink of something?’ he says. I must look really ill, I think.

‘Just some water. Thank you.’

‘No worries.’ He stands up, then reaches into his pocket and hands me an envelope.

‘What’s this?’ I open it and find a thick bundle of twenty-pound notes.

‘Rent.’

‘What? We’ve been through this. I don’t want rent from you, love.’

‘Well, food, bills – whatever. It’s yours.’

I turn to Simon, remembering how insistent he’s been lately that Justin shouldn’t have a free ride. He shakes his head, as if to say it’s got nothing to do with him.

‘That’s really good of you though, Justin. Well done, mate.’ The colloquialism sounds forced on Simon’s lips and Justin looks at him scornfully.

‘I thought you were skint?’ Katie says, peering at the notes to see how much is there. I put it in my cardigan pocket, trying to ignore the voice inside my head that wants me to ask where it’s from.

‘Melissa’s put me in charge of the café so she can set up the new one,’ Justin says, as though he’s read my mind. ‘It’s only temporary, but it comes with a pay rise.’

‘That’s wonderful!’ Relief that my son is neither stealing nor dealing makes my response disproportionately enthusiastic. Justin shrugs as though the news is of no importance, and goes into the kitchen for my water. ‘I always knew he just needed a break,’ I whisper to Simon. ‘Someone who could see what a hard-working lad he is.’

I suddenly remember Justin isn’t the only one with job news. I turn to Katie. ‘I’m so sorry I wasn’t more supportive before your audition, love. I feel dreadful about it.’

‘Oh God, don’t worry about that now, Mum. You’re not well.’

‘Simon said it went brilliantly.’

Katie beams. ‘It was amazing. So, the agent didn’t take me on, because she already had a few on her books with my look and range – whatever that means, but I got chatting to a guy who was waiting in reception. He’s the director of a theatre company putting on a production of Twelfth Night, and their Viola has just had a skiing accident. I mean, how perfect?’

I stare at her, not following. Justin returns with a glass of water. He hasn’t let the tap run, and it’s cloudy and tepid, but I sip it gratefully. Anything to ease my sore throat.

‘Mum, Twelfth Night was the text we did for GCSE English. I know it inside out. And he said I was made for Viola. I literally auditioned then and there – it was the maddest thing – and I got the part! The rest of the cast have been rehearsing for weeks, but I’ve got to nail it in a fortnight.’

My head is spinning. ‘But who is this guy? Do you know anything about him?’

‘He’s called Isaac. Turns out his sister went to school with Sophia, so he’s not a complete stranger. He’s done stuff at Edinburgh, and – here’s the exciting bit – they’re going to take Twelfth Night on tour! He’s incredibly ambitious, and so talented.’

I spot something else in Katie’s face. Something other than her excitement over an acting job. ‘Good looking?’

She blushes. ‘Very.’

‘Oh, Katie!’

‘What? Mum, it’s all kosher, I promise. I think you’d like him.’

‘Good. You can invite him over.’

Katie snorts. ‘I only met him yesterday, Mum, I’m not asking him to meet the ’rents.’

‘Well, you’re not going on tour till you do, so …’ We glare at each other, until Simon intervenes.

‘Shall we talk about this when you’re feeling better?’

‘I’m feeling better now,’ I say, but my stubbornness is undermined by a wave of dizziness that makes me close my eyes.

‘Sure you are. Come on, you: bed.’

I remember his promise. ‘Did you call the police?’

‘Yes. I spoke to someone senior on the investigation team.’

‘Rampello?’

‘I think so. I said how worried you were about the advert – the one that looked a bit like you—’

‘It was me.’

‘—and the guy I spoke to said he could totally see why you were anxious, but at the moment they don’t think Tania Beckett’s murder is linked to any other crimes.’

‘There has to be a link,’ I persist. ‘It can’t be coincidence.’

‘You don’t even know her,’ Justin says. ‘Why are you getting so wound up?’

‘Because she’s been murdered, Justin!’ He doesn’t react, and I look at Katie in despair. ‘And because my photo—’

‘—it wasn’t your photo, sweetheart,’ Simon interrupts.

‘—because my photo was in exactly the same advert as hers. So I think I’ve got every right to get wound up, don’t you?’

‘Those sorts of ads don’t normally come with premium-rate numbers unless they’re dodgy,’ Simon says.

‘What’s that got to do with anything?’

‘Was she an escort?’ Katie asks.

‘Occupational hazard,’ Justin says. He shrugs and assumes his previous position on the sofa, phone in hand.

‘They said on the news she was a teaching assistant, not an escort.’ I think of the photo they used in the paper, of Tania with her boyfriend. I imagine the headline above a report into my own murder, and wonder what photo they’d put alongside it; whether they’d ask Graham Hallow for a quote.

‘The advert didn’t say anything about escort services, did it, Mum?’ Katie says.

‘It had a web address.’ I press my palm against my forehead, trying to remember. ‘Find the one dot com.’

‘Sounds more like a dating site. Maybe she was killed by someone she met online.’

‘I don’t want you going out on your own any more,’ I tell Katie. She stares at me, aghast.

‘Because of one murder on the other side of London? Mum, don’t be ridiculous. People are murdered all the time.’

‘Men, yes. Boys in gangs. Druggies and stupid risk-takers. But not young women on their way home from work. You go out with a group of friends, or you don’t go out at all.’

Katie looks at Simon, but for once he backs me up.

‘We want you to be safe, that’s all.’

‘It’s not practical. What about work? I don’t finish at the restaurant on a Saturday night till ten thirty p.m. and now I’m in Twelfth Night I’ll be rehearsing most evenings. There’s no alternative but to come home on my own.’ I go to speak but Katie interrupts me, gently but insistently. ‘I’m a big girl, Mum. I’m careful. You don’t need to worry about me.’

But I am worried. I’m worried for Katie, as she travels blindly home from work each night, her head in the clouds thinking about red carpet stardom. I’m worried for all the Cathy Tannings and Tania Becketts, who had no idea what life had in store for them. And I’m worried for me. I don’t know what those adverts mean, or why my photograph appears in one, but the danger is very real. I can’t see it, but I can feel it. And it’s getting closer.