It’s funny, it was only six months ago that I came across her letters. A stash of them the width of a hardback, neatly addressed in a tight, round cursive. These were the flat, grey days between Christmas and New Year. M and I sifting through the paper remnants of our younger lives under the glare of the big light. He had theatre programmes and newspaper cuttings. I had love letters from the girls I grew up with.

I deliberated over keeping them. We were making room for the baby. I can be ruthless in these situations, pushing aside anything that doesn’t hold a use immediate for that moment, hungry for space. I hadn’t, I told M, spoken to some of these girls for over a decade. Not seen them in longer. ‘You should keep them,’ he said, ‘they’re what your life was’. These small, stickered pages held the trappings of a girlhood I’d let go of - small panics over driving between the countryside villages we inhabited and Northampton, 30 miles away. Notes on the bread we ate on our holidays. Daft gossip about people we’d done a summer job alongside. I had forgotten how sweet we were, how nervous about the world. I put them back in the box, harboured a quiet intention of using them for writing research one day.

We sent letters because we’d left the homes we’d grown up in. We had met at school, finding one another in our early teens and knitting the kinds of friendships that don’t emerge later in life: hard and fast and so close that later privacies were unthinkable. We’d walk into one another’s houses, we’d idly tap through each other’s text messages, we were free and open and vaguely disgusting with our changing bodies. We occupied the space that lovers would later, with less grace.

It was a cold afternoon when the message came through; our wedding anniversary, the baby was exactly two weeks old. “Al, is this you?” Only a handful of people use that version of my name now - they have all known me from childhood. “I’m sorry it has taken me years to write this message. Hard to find the words.”

She is a writer, always has been. When we were girls I marvelled at her ease of wordplay, at the nicknames she’d dream up and the snippets of conversation she’d cling onto that would become in-jokes and tokens with far greater longevity. But here was one that had been kept on pause for years. We didn’t fall out so much as drift away into different lives. We’d lost the words, I guess.

Now they appear in the strange blue light of a phone screen. We’d never known this immediacy. Our written relationship was formed on MSN Messenger and Nokia 6210s, hers were among the 10 text messages the latter had capacity for. And the post, of course. Postcards from summer holidays, letters with university dorm room addresses. By the time BBM and WhatsApp came along we weren’t using them.

So here we are: women with babies, husbands, houses and a history of who we used to be. I’ve thought of her often, I tell her. I hope she’s been ok. But it’s easier to pick up where we are now, with the baby sick and the sleepless nights and the all-consuming minutiae of domestic life. And yet there is such familiarity in our patter. I shed any self I may have grown since; I recognise her voice like an old song on the radio. Nostalgia presents itself like a foil milk bottle lid and we alight on it, magpies, stitching it into these new nests that we’ve made. We exchange photos of our children, we check in on one another’s days. Some things remain deeply the same even when everything else has changed. Somehow I became the writer, but she’s still the poet. Her words float stealthily into my inbox and I read them on the bus, wet-eyed because I’m seen, and I’ve always been seen. What it is to think you’ve been forgotten, when all along you’ve been known so deeply.

This rekindling has been so potent that I’m almost shy of it. I don’t really know how to explain it to M or our mutual friend. It feels almost impossible because it is: here is someone I’ve barely spoken of but I love fiercely. I am processing it too.

Tomorrow I shall take the baby out and onto a bus to a train to see her. She wants to see us. It has been a long time. I wonder if her hair smells the same.