My mum was a teenager when she fell pregnant with me. She was in love with a man 10 years older, and after I was born it was decided that my father’s relatives would raise me just outside Manchester. No one spoke about Mum – I never saw any baby pictures or birth certificate. I assumed I’d been an accident. I remember crying in bed one night, aged about 10, wanting Mum, even though I didn’t really know who mine was. But that faded over time. I got used to my setup: mums were for other kids.

Eventually, I was shown letters from Mum, revealing that she was a drug addict. She gave birth to me, her second child, at 19, by which time she was addicted to heroin.

All this was running through my head as I arrived in Glasgow on 27 December last year. I was 22 years old. My sister Leanne, from my mother’s side, had tracked me down on Facebook, and we had been messaging for a while, but had met only once or twice. Leanne had been brought up by our mother’s parents, and had some contact with her throughout her life. She was now living in Canada, but returning for Christmas and desperate to see all the family together. A big party had been arranged to welcome her back, and everyone would be there, including our mum.

For the first time in my life, I knew exactly where my mum would be. She had never felt real before. At pretty short notice my sister and I hatched a plan. I’d meet my sister as she arrived at Manchester airport, then the next day we’d drive up to Scotland in secret. Keeping it a surprise gave us an adrenaline rush. I could, of course, have arranged the meeting properly and given Mum advance warning – but I feared she’d spend the whole intervening time over-thinking the 20 years we’d spent apart. I also knew that I might panic and back out at the last minute, and that would be unspeakably cruel.

In the car, I could hardly change the radio for my rattling nerves. It was about a four-hour drive. I asked my sister everything – lots of questions. I asked her about Mum’s job, her interests, her relationship history, her favourite music, if she’d care that I’m gay.

“What’s her personality like?" I asked.

"Like yours," my sister said.

"What does she look like?"

"Quite like you..." she said.

We were there. In this otherwise unexceptional row of terrace houses , on the periphery of Glasgow, was my family. The steps were icy and the air cold. As the door opened, my sister ran in to the squeals of a family reunited. “You won’t believe this,” said a woman I now know to be my aunt, who was hosting the party. Just a door separated us now. I stepped into the room. I’d never called someone “Mum” before. But there she was.

We embraced and were soon chatting away. We could hardly get the words out fast enough. Seeing someone so alike looking back at me was the strangest, most comforting experience. She looked like me, had mannerisms like me. She had the same-shaped chin and unfortunately large forehead as me. And, almost embarrassingly, the same haircut. Though a lifetime may have separated us, this woman at a party in Glasgow was my mum. She stared at me for a split second, before grabbing me for the sort of don’t-let-go hug you give a newborn baby. All she could say was that she never thought we’d meet again. She couldn’t believe we had.

She’d been clean of drugs for five years. She told me how she now works for a charity that helps young people overcome the same issues she had. I hadn’t met Mum because I wanted to like her; I just wanted to know that she was there. But I do like her. We now talk regularly, and I feel proud she’s my mother. That’s something I couldn’t have even imagined when the door opened to her at that Christmas party. Life may be short, but it’s always long enough to reconcile.