How do you know someone has stopped drinking? Don’t worry, they’ll tell you. The old vegan joke comes into my mind a lot as yet again I start talking about how my life has transformed since I gave up booze. But people mostly humour me, sometimes even seek me out. It’s amazing the number of conversations I’ve had at parties where friends with whom I used to get hammered now sidle up to me between their fourth and fifth drink and mutter about how they’re starting to wonder about whether they should quit, too.

As long as I don’t use the A-word. Alcoholic. That doesn’t make anyone comfortable. You weren’t that bad. And if your definition encompasses literal gutters, I wasn’t (though I’ve fallen off a fair few pavements in my time). Leonard Cohen’s words from You Want It Darker could have been written for me: “I struggle with some demons, they were middle-class and tame.” Making a fool of myself on one bottle too many of barolo at a dinner party is hardly alcoholism, after all.

But I think I was that bad. However respectable your dinner parties or expensive the alcohol you knock back, there are only so many blackouts a middle-aged mum should have. I was just lucky that the structures of my life were enough in place that my alcohol-use disorder remained highly functional and that I’ve been able to address it without too much drama. Hopefully, even in time. In a recent piece by former Loaded editor Martin Deeson in the Times, he quotes Ozzy Osbourne: “They either give up at 50 or they’re dead by the time they’re 60.” I was 49 when I had my last drink.

Like all the best quit lit, it starts with the agony of being 14, the way that social anxiety evaporates with the first sips of whatever alcohol we can get our hands on. I grew up in Edinburgh and drinking underage really wasn’t a problem. The off-licence on George Street was happy to sell discounted vermouth to friends of mine wearing school uniform – not even a pretence at age-limit due diligence. At 15 I drank so much and so fast at a formal ball that I threw up all over the table while dining at the Signet Library. Shaming, yes, but at least I went on to get straight As at O-level.

Thus the pattern began. The screw-ups were bad, but I got away with them. That’s the issue with being highly functional.

Summer in the early 2000s. Barcelona. I’d had gastritis before, painfully recurring indigestion from binge after binge. Jack Daniel’s was always the main culprit and this Spanish escapade was no exception. On a night out with European friends who didn’t understand the drive I had to get completely obliterated, they pointed out quietly that there was no need for me to order double measures every time, or knock the drinks back so fast. I didn’t listen and paid the price, losing most of that night blackout drunk and resurfacing the next day with a hangover worse than most. Caught short in the station, I couldn’t get to a loo in time and threw up into a bin – a long, steady thread that felt weird and looked weirder. When I put my hand up to my mouth, it was blood.

That was a warning sign. I sat on the train from Barcelona, deciding I should never drink again. When I got to the hotel I made a list of my top drunken moments, my love letter to alcohol. I stopped when I got to 50. Downing pints faster than the rugby team at college. A night in my mid-teens on the shores of Loch Rannoch when I finally got drunk enough to snog the boy I liked. Tequila and midnight blue skies at the end of A-levels. A party on the beach in Gullane with an unromantically named bloke called Terry. In all the flashbacks I was gorgeous, dancing, a swoop of glory on a rising star.

In my first novel, there’s a scene where the main character drunkenly sings karaoke. She thinks she’s brilliant. The next day, her husband shows her the video that he made of her performance and she sees the truth of it. A dishevelled woman, makeup running down her face, caterwauling along to the Smiths. We never see that we are the drunkest in the room.

The blood didn’t put me off, the resolve didn’t last. Within days I was at a wedding in Madrid with a free bar serving vodka and Red Bull, which truly did give me wings. I’d got away with it again.

Through my 20s I was a criminal barrister. I grew up reading about Rumpole of the Bailey and his Château Thames Embankment. It was only natural that when I started at my practice, I gravitated towards the drinkers who went to the pubs on Fleet Street every night. There were long stretches of time that dinner consisted of five pints of Stella and a packet of crisps. I can’t kid myself I was getting away with it then; I was systematically sabotaging myself, falling over in chambers in front of senior barristers and turning up late and hungover the next day.

The shame the morning after is always real, the horror of piecing together the night before. Don’t tell me don’t tell me as the calls from concerned friends start to come. The massive black bruise on my upper arm after a night in Pimlico, the cuts on my feet from the broken glass on the floor of a night club in Holborn when I refused to put my shoes back on. Taking taxis because I was too hungover to drive; avoiding people I barely knew for months after incoherently accusing them of gatekeeping and being in a playground gang. All the rage and sadness I repressed sober that haemorrhaged out drunk.

Rock bottom is a strange concept. It allowed me to put off a proper reckoning for years. It wasn’t that bad. I wasn’t that bad – I drank less as the years went on, after all. I could moderate my drinking, cut back. Match the slowest drinker in the group sip for sip. I didn’t drink every day of the week. I didn’t drink on my own. I didn’t drink in the morning. I planned my drinking for the evening ahead. I didn’t drink and drive. I wasn’t sabotaging my work any more and besides, I’d been a terrible barrister. Crime writing’s the sort of job you’d expect a drinker to do. But alcohol still took up too much space in my mind.

Nearly all the presents I received on my 40th birthday were alcohol themed. Bottles of champagne, a sequined purse in the shape of a gin bottle. Endless cards talking about wine o’clock and why mummy drinks. I was mortified. Not enough to stop me, though. Later on, when someone in the publishing industry died and every social media post commemorating them was a photograph of a glass of champagne or a negroni, I thought about the pile of gifts I’d eyed with such shame. I didn’t want that to be the way I was remembered if I went prematurely, me red-faced, laughing incoherently, gin in hand.

One of my best friends died in April 2021. It was cancer, it was terrible, and it was emphatically not alcohol related in any way. But we were born within two weeks of each other and seeing her life cut so short was a moment of reckoning for me. I could keep on as I was going, or I could face up to the fact that I was more than a pickled brain in a pickling jar. It was time to take care of myself.

My last drink was on 7 June 2022.

To return to Ozzy Osbourne, what he’s talking about is known as sniper’s alley, this time in our early 50s when it’s the last chance to make changes before we start being picked off one by one. A couple of friends have already succumbed to addictions, their premature deaths awful to see. I’ve maybe left it too late to undo the damage I’ve done to myself, but I’m giving it my best shot. Yoga, weights, running. I might even give cold water swimming a go…

I’ve faced up to it. Some of my friends might argue you weren’t that bad. But my name’s Harriet and I’m an alcoholic. I don’t go to meetings, but I go to therapy every week. I repeat the mantras. One day at a time. Keep my side of the street clean. In my own way I’ve worked the steps. I’m at peace with the shame of the past; I love waking up each morning with a clear head, clearer conscience.

If I die tomorrow, I hope I’ll be remembered, but without a glass in my hand.

A Lesson in Cruelty by Harriet Tyce is published by Wildfire at £16.99. Buy it for £14.95 from guardianbookshop.com