MY mum’s friend Louisa* had three children, but I only met two of them. Years later, I found out the reason. Her oldest son Paul* had gone missing in his late teens, and no trace had ever been found.

According to my mum, Louisa talked about Paul quite naturally. When she told a story and Paul happened to be in it, she said his name without hesitation. She didn’t sanctify his memory: the stories where he did something loving or funny or cute where balanced out with those where he was an amoral agent of chaos, whose actions rained catastrophe on everyone around him. (My mum said rather gloomily that Paul sounded like he’d been a bit of a handful.)

Did she ever say what she thought might have happened? Of course I didn’t ask Louisa - there are some questions even a nosey writer knows better than to ask - but I felt comfortable asking my mum. She said she thought he was probably dead, my mum replied. She wished she could know for sure, but she was also glad not to know in a way, because then she could still hope he might still be alive and might come home to her some day.

When you lose track of your child, you can build an entire catastrophe in moments. The fear you feel can be out of all proportion to what’s actually happened. I once lost my daughter in a supermarket (she stopped to look at cereal, we walked round the end of the aisle, she thought we’d gone the other way and ran in the wrong direction). In hindsight, she was “missing” for about four minutes. At the time, those four minutes seemed to last for ever.

I remember thinking, very melodramatically, no-one is leaving this supermarket until my daughter is found! But what if the four minutes just kept stretching out? What if your child was gone so long, people had no choice but to leave? What if you finally had to leave the place where you lost them too? How would you cope with knowing that everyone who had helped you to look for them was now going to stop looking, and get on with the rest of their lives?

The thought of living a life with that blank silence at the heart of it – no clues, no more information, just that endless void of waiting – terrifies me. I imagine it terrifies most parents. But at the same time, that silence contains a grain of hope. For so many stories of long-term disappearance, the ending is the discovery of the missing person’s body.

So which is worse? Hoping they’re not dead, but wondering what kind of horror they might be living through? Or knowing they’re gone for ever?

Then, of course, there’s the assignment of blame. It’s human nature to blame the parents. They should have been supervising better, been paying more attention, put their children first, stayed in the room with them, not let them out of their sight, not pushed them so hard, not let them slack off, listened to them more, not been so intrusive, not let them hang out with those friends, not stopped them from hanging out with those other friends, given them more freedom, given them less freedom, given them a phone, not given them a phone.

As long as we can blame the parents, we can kid ourselves that we’d do things very differently with our own children, and therefore this awful thing can never happen to us. Now imagine you are one of the parents. What if you secretly think it’s your partner’s fault that your child wandered off or ran away, and is now lost? What if they secretly think the fault lies with you?

My novel The Winter’s Child begins with a woman in torment, trapped in that endless conflict of guilt and shame and resentment, wanting to know the truth, but also wanting to keep hoping. Susannah Harper’s son has been missing without trace for five years. Visiting Hull Fair one night with her sister’s family, she finds herself outside a fortune-teller’s caravan. With all leads pursued to their fruitless ends and with no-one left to consult, she finds herself compelled to go inside and seek out answers. She knows that the fortune-teller can tell her nothing of worth; she knows that finding her lost son Joel will almost certainly mean knowing he’s lost for ever. But she’s still driven by that need to know.

Each year in the UK, around 100,000 children are estimated to missing. Almost all are found within 48 hours: 99 per cent are found within a year. The Winter’s Child is a story about a boy who stayed lost, and his mother’s desperate search to find him.

n The Winter’s Child by Cassandra Parkin (Legend Press), available online and in bookshops

* Names have been changed