Before heading out to a friend's birthday party last month, I mentally ran through everything I needed. Make-up, bottle of wine, flat shoes for the way home.
Then I double checked my Mulberry handbag for the treat I'd been looking forward to all day: a tiny plastic bag containing a wrap of cocaine.
I knew I shouldn't and had, in fact, been promising myself I wouldn't ever since the invitation arrived. But here I was, with a stash of Class A drugs tucked into my reading glasses case.
The excuses were all there: I'd had a tough week. I was unhappy. I needed a treat. And of course the clincher - this absolutely would be the very last time.
That night, two friends and I took it in turns to slip away to the bathroom and snort a line, returning feeling energised and far more confident. We were careful not to draw attention to ourselves, aware the other guests would have been appalled.
For most of my circle of middle-aged, middle-class professionals, drugs were the preserve of a reckless youth, not for responsible parents like us. And until recently, that was my attitude too.
But two years ago, at the age of 52, after being battered by a perfect storm of an acrimonious divorce, menopause, an empty nest and the pressure of looking after my frail elderly mother, I suddenly I found myself with a drug dealer in my contacts list, and a weekend cocaine habit.
Judging by the friends who are willing to indulge with me - the majority of them fellow divorcees - this is more common among 50-something women than you might think.
According to the ONS, while cocaine use among young people is declining, it's booming among Generation X, born between 1965 and 1980. Recent figures show almost a third of those in treatment for addiction are now aged 50 or over, compared to just 12 per cent in 2010.
So-called 'silver snorters' like me also account for the highest rates of deaths due to cocaine misuse. And new research from the University of Cambridge shows using cocaine almost doubles your risk of having a stroke in later life - with myriad other health implications.
Of course, as a highly-educated woman, I'm aware of the risks, which fill me with self-reproach. I know many readers will wonder how I could be so stupid - and selfish - especially as I have two children, now aged 18 and 20.
But the buzz of cocaine has proved to be the release I need from life's responsibilities and disappointments. For a few hours, I can forget about my ex-husband's beautiful new girlfriend, the stress I'm under at work and the thought of lonely old age.
Since starting, I've kept telling myself I have to stop. Then another stressful day, another nasty solicitor's letter, would arrive - and I'd find myself making 'that' phone call once again.
The first time I took cocaine was in my 20s, at a party with colleagues while working in recruitment. I was curious, having got through my university years on nothing stronger than cheap Chardonnay.
I remember doing my first line and thinking, is that it? There was no dramatic rush of euphoria, although I did have more stamina, drinking more and staying up later.
The real appeal was how much less self-conscious it made me. I've worried what people think of me all my life, but cocaine turned me into a social butterfly.
After that, cocaine became only an occasional part of my life, but all that changed when I met my husband Daniel, an accountant, when I was 30.
Early on in our relationship, I took him on a night out with my work friends, and he declined to take any cocaine himself. Later, when he told me he found the group's company tedious, even I had to admit he had a point; on cocaine, some of my male friends enjoyed the sound of their own voices rather too much.
By the time we married two years later, I was happy to consign cocaine to the past. I was blissfully in love and after our son and daughter arrived when I was 34 and 36 respectively, we settled into family life in our four-bedroom house in South London.
We both managed to rise to senior management positions, enabling us to send our children to private school and go on annual skiing holidays. But our social life, such as it was, consisted of low-key dinners with friends who also had children.
Sadly, as the years ticked by, Daniel and I began to neglect our marriage. We both worked long hours and would fall into bed too exhausted to say 'goodnight', let alone have sex, which became a rare event - as did any meaningful conversation.
Looking back, I suppose the red flags were there. Daniel started to take more care with his appearance, joined a gym, and would frequently come home late after client dinners.
Yet I didn't for a minute think he was having an affair. So when he suddenly announced one evening two years ago - right after dinner as I was loading the dishwasher - that he wanted to separate, it was a devastating shock.
He quickly moved into a flat, leaving me reeling while trying to put on a brave face for the kids, then 16 and 18.
A few months later, a friend told me she'd seen him in a local pub with another woman. He swears they were set up by a mutual friend after we split, but obviously I couldn't help but assume he'd been cheating on me.
Looking back, I'm so proud that I managed to hold it together during that horrible time. Aside from taking a few weeks off work, I was determined not to wallow. I began exercising regularly, prioritised eating healthily and lost weight. But behind my brave smile, I was very lonely and unhappy - and I tortured myself with thoughts of Daniel and his new girlfriend.
Some low-level online stalking confirmed my worst fears; she was younger than me, and slimmer.
One weekend, when my daughter was with her dad and my son having started his gap year, I found myself sitting alone in my big, empty house unable to stop crying.
My friends rallied round, and one insisted we went on a girls' night out. We started at her house, and after a few drinks, she took me to one side. She had 'just the pick-me-up' I needed, she said, with a naughty twinkle in her eye, and led me through to her study where she began chopping up a couple of lines of cocaine on her a Soho Home coffee table.
I was shocked; I had no idea she took drugs. But we were both tipsy and it seemed exactly the kind of illicit fun I needed.
That night, I felt carefree in a way I hadn't done in a very long time. When I got home at 3am, I was too wired to sleep, so I danced around my living room to my favourite Nineties songs.
It may seem sad to some, like I was trying to recapture my lost youth, or even having a full-blown midlife crisis, neither of which I'd completely deny. But at a time when my life felt so heavy, cocaine made me feel alive.
The next day, however, I felt exhausted and anxious. When my daughter arrived home that evening, I was full of self-reproach. What on earth was I doing? I was supposed to be steering her through her impending exams and the breakdown of her parents’ marriage, and here I was, sleeping off a ‘big one’ like the reprobate youth I warned her about.
When, a few weeks later, I was on a girls’ night out again, I swore I would just stick to wine. But then a friend - a different one this time - raised a quizzical eyebrow and asked whether I fancied a ‘cheeky bump’… and I hesitated for all of three seconds.
The next time we went out, ashamed of being the one scrounging off my friends, I offered to call the dealer myself.
It felt surreal, standing outside my nice house, on my nice street, with a clutch of £20 notes in my hand, waiting for some stranger to appear on a moped. What if the neighbours spotted me? What if it was an undercover police officer?
But in a flash, the exchange was done. Soon, it became second nature.
Over time, I learned to subtly sound out friends to see who was open to it - four or five could usually be persuaded - most of them divorced mothers like me. We'd usually meet at one of our houses, and it just adds a little sparkle to the evening.
Yet at that birthday party last month, I must have been more out of it than I realised because I'd lent a friend my house key to do a bump - and hadn't noticed she'd kept it afterwards.
I only realised when I found myself locked out in the small hours. I took an Uber to my friend's house to collect the key, feeling foolish, ashamed and a little terrified. It made me realise how vulnerable I was making myself, and I vowed, there and then, that it had to stop.
I'd never want my children to know what I've been doing. I've always been hardline when it comes to them trying drugs, which I know makes me a hypocrite. I think they would find it embarrassing; tragic even. I hate that thought.
In the wholesome weekends with my daughter since that fateful night, it's been easy to forget that side to my life. But I know the next invitation to a girls' night can't be too far away. Despite my newfound determination to quit, I worry I'll waver.
Now 54, I hate the thought of me doing this in my 60s - if I even make it that far.
My daughter is taking her A-levels this summer; then hopefully will be off to university soon after. Around that time Daniel and I have agreed I'll sell our marital home & downsize. I hope this will signify a fresh start.
But despite all my best intentions amid ongoing stresses can I say hand on heart that I'll never touch cocaine again? Worryingly; I don't know if I can.