Guilt: The Sunday Times best selling psychological thriller that you need to read in 2018. Amanda Robson

Because you’re a cutter.

      And twice you have cut too deep.

      Once, a very long time ago when we were at school. I still remember that winter afternoon so clearly. Walking to meet you from your netball session, after my hockey had finished. A perfect winter afternoon. Sunny, with a nip in the air. The sort of afternoon that fooled for a second, making me believe I was walking through a ski resort. But something was wrong. People were staring at me. Whispers on the wind.

      ‘Zara. Zara Cunningham.’

      ‘They called the ambulance and the police.’

      The PE teacher told me what had happened.

      ‘Your sister slit her wrists.’

      A slow creeping numbness seeped through me.

      ‘The PE assistant found her unconscious covered in blood. This afternoon, just before netball.’

      ‘Is she all right?’ I asked with a tremor in my voice.

      The PE teacher put her hand on my shoulder. ‘We found her in time. I am sure she’ll have regained consciousness by now.’

      In time. Regained consciousness. The PE teacher’s words jumped in my mind. Zara, I wanted to know how you could do this to yourself. How could you try to take your own life? You whose life always seemed so much more interesting, so much more carefree than mine.

      But it wasn’t like that, was it? You hadn’t tried to kill yourself. Cutting seems to give you some sort of euphoria.

      ‘I cut to take the pain away,’ you told me later. ‘And to stop the panic attacks.’

      ‘What pain?’ I asked. ‘How can more pain take pain away?’ I paused. ‘And what panic attacks?’

      The second time you cut too deep by mistake was only six months ago. Just when Mother and I thought that maybe at thirty years old, after so many years of antidepressants and CBT, maybe you had stopped doing it. A phone call to Harrison Goddard to inform me. Just as I was tidying my desk, about to go for lunch. Mother’s voice on the line, riddled with panic, only just recognisable.

      ‘Come quickly Miranda. She’s slit her wrists again. Deeper this time. The paramedic said it’s touch and go whether she’ll survive.’

      I left work immediately. I drove up the motorway to our hometown, the world passing me in a blur. When I arrived at the hospital I scrambled out of the car and allowed the place’s sprawling bowels to swallow me up. I felt as if I was floating. The hospital seemed to move around me. People being triaged. The reception desk protected by an armoury of glass, with only a thin slit for conversation. The receptionist was busy. Tapping a computer keyboard with her long blue tapered fingernails. No time to look up. The phone on her desk rang. She picked up, frowning as she listened.

      ‘OK, OK. Will do.’

      She put the phone down. At last she looked up and noticed me. ‘Can I help?’ she asked.

      ‘I’m looking for my sister, Zara Cunningham. She was admitted earlier. My mother is with her.’

      Blue fingernails stabbed at the computer keyboard again. ‘She’s in Critical Care. I’ll get a nurse to take you to her. Wait by the door to A&E.’

      ‘Thanks.’

      I stood by the door, as requested. Bracing myself to wait for a long time. But no sooner had I arrived than a plump, blonde nurse wearing a pink uniform was putting her head around the door asking me whether I was Ms Cunningham. No sooner had I said yes than I was escorted into the unknown depths of A&E.

      ‘I’ll take you to find your mother,’ the nurse said.

      ‘Can’t I see Zara?’ I asked.

      ‘Not right now.’

      The panic that had been simmering inside me for hours became volcanic. ‘Why not?’ I asked.

      ‘A team of doctors are assessing her at the moment.’

      A team of doctors assessing my sister who’s slit her wrists. A team of doctors assessing my sister, who was laughing and joking with me on the phone the previous evening. Just under twenty-four hours ago. The nurse and I walked past cubicles containing people in distress. A man lying on his back with a protruding stomach, his mouth covered by an oxygen mask. A young child giving a bloodcurdling scream. A woman with a black eye and a bloodied nose.

      Through A&E.

      Right and right again. Along a corridor with windows to a small garden with pebbles, ferns, and rubbery plants. The pink nurse stopped by a soap dispenser at the entrance to Critical Care. I washed my hands with something that looked like cuckoo spit. And then finally she led me to a small seated area where my mother was waiting.

      My mother, but not my mother. A woman wearing a facial expression that my mother never wears. She stood up. She walked towards me. She held me against her. Holding me so tight as if she wanted to engulf me. She felt like my mother. She smelt like my mother. Of love. Of despair.

      Deborah Cunningham of Heathfield Close, Tidebury, Lancs.

      Heathfield Close, an oxbow lake of modern housing, at the right end of town. Wide pavements. Leafy streets. Divorced from my father when we were toddlers. He moved to the States. We never saw him again. Mother working her socks off as a teacher, to support us. Always responsible for us alone.

      ‘How is she?’ I ask.

      ‘No news yet.’

      ‘Can I get you anything? Tea, coffee, anything?’ the nurse asks.

      ‘My daughter back,’ Mother said.

      ‘We’re doing our best.’

      The nurse evaporated, I don’t know where. Mother turned on the small TV mounted on the wall in the corner. But I did not watch it, figures just moved about on the screen in front of me, and I thought of you, Zara. Of holding you, touching you. Asking you why you had done this again after so much help, so much therapy. You always said you cut to feel better. But was it true? Or did you really want to kill yourself?

      The previous time this happened, so many years ago, you denied that suicide was your motive. But it is hard for someone who doesn’t understand cutting to really grasp the significance of its euphoria.

      This time, the second time, somehow, I don’t know how, Mother and I managed to contain ourselves, as hours and hours passed. I felt as if I was sitting in a vacuum. My life had stopped and I would only feel better if I got you back. At last a doctor was walking towards us, stethoscope around his neck. We did not stand up to greet him or walk towards him. We did not have the strength. We sat and watched him approach, transfixed, waiting for news. He stood in front of us, a half smile in his ice-blue eyes.

      ‘Zara is stable. She has regained consciousness. All the neurological tests are positive.’

      Stable. Positive. Neurological. Words tumbled in my head and for the first time in hours I stopped having to concentrate to breathe.

      My stomach tightens with worry. What are you doing now, Zara? Why have you been gone so long?

      You finally return to my flat after your trip to Tesco, over an hour later, looking flustered.

      ‘What’s the matter?’ I ask, unable to disguise the anxiety in my tone, as you waltz through the door, placing two microwaveable boxes of chicken tikka masala on the kitchen table and sighing noisily. You are wearing your Doc Marten boots and a floral skirt with a creamy background that always looks a bit grubby. I do not like your nasal piercing. I do not like the way you have sliced into your hair, just on one side, above your ear, with a razor. I don’t think it suits a woman of your age.

      ‘I’ve met someone,’ you say.

      The word someone hovers in the air. A word of importance. You are always meeting people, laughing with them, talking to them, dating them. But never someone. Not until now.

      ‘Someone?’