When the bus lurches to a halt at the top of Brixton Hill, I stumble off and hurry home, letting myself in with clumsy hands. Without even taking off my shoes or coat, I sit down at the kitchen table, open my laptop and log into my Facebook account. I haven’t posted anything on here in months. Sometimes I’ll share something from someone else’s timeline: one of the random people I’ve friended, just because I thought their page looked nice. Maybe they had a picture of a cat, or some scenery that I liked the look of. Only that, and posts from the Child Brain Injury Trust.

Even on Facebook, where you are free to make friends with anyone, I don’t really have any. The tab at the top lists the number as seventeen. But almost none of them are people I know in real life. But there is a private group on here that, once upon a time, I belonged to – a private Facebook group for the office I worked in. I made hardly any use of it at the time, but now I’m desperate for it still to be there. I have to rack my brains to remember the name of it and I end up putting in combination after combination of words before I hit the right one. And yes, I can hardly believe it – it’s still here.

I have to take a few breaths before I can go on. Then I scroll down through the history of posts and comments, names coming back to me, blurry faces, as I’m bombarded by a ticker-tape of memories. I can almost feel myself falling back in time and it’s a dislocating sensation. No messages from Sarah, but that’s not what I’m looking for. I click through the pictures, the photographs, the memes. To begin with there are flurries of posts, each with dozens of comments. People sharing silly quotes, silly pictures, silly jokes. I click on them, opening up each thread in turn, line after line, the print so tiny. But then over time, the posts dry up, the comments peter out, the group page runs dry. People drift away, losing interest. No one has posted there for – I calculate – eighteen months.

My stomach clenches; I should probably eat something. Instead, I click into the space for a new post in the group. To begin with, I hardly know where to start; I type and delete three openings. What on earth am I supposed to say? The situation is so horrifyingly bizarre, how can I distil that into a post for people I haven’t spoken to in years? But I have to write something. There are so many unanswered questions, ones that an inquest is unlikely to clear up. What happened to you? What happened? How did you end up so alone?

So I keep going, writing and rewriting, until I’ve got close enough.