It is no secret that bestselling author and columnist Bryony Gordon is a recovering alcoholic and former cocaine user, but even the most unshockable of us might flinch at some of the things she did while under the influence.

She recalls waking up drunk and drugged lying on damp grass, a man's head between her thighs. That man was not her husband - he and their daughter Edie were half a mile away sleeping in the grounds of the country estate they were staying at to celebrate her friend's birthday.

Gordon was 37 and when the man, who had given her cocaine, phoned up the following week asking if she was still up for a threesome, she realised she didn’t know herself, or what she had said or done, while intoxicated that night.

"I was so ashamed of my drinking. The shame is what kept me in it and kept me ill and unwell. It was miserable, and only when I finally got help did I realise I was not the only one behaving in the way I was and that I wasn't a bad person, I was an ill person," Gordon says today.

She has charted the journey through alcoholism and subsequent recovery in her no-holds-barred new book, Glorious Rock Bottom.

"My husband [financial journalist Harry Wilson] knows all of it. I've always been very honest with him about what happened when I was drinking. We've worked through that.

"It would be very different if I was still behaving in that way, but I'm not. I'm nearly three years sober. But it's really important that we don't flinch from that stuff because it happened and we need to talk about it."

Gordon, a gregarious, party-loving spirit, had been an alcoholic for some years. On her wedding day, she was drunk and high on cocaine. Her regular drink of choice was ale, which had slightly less alcohol than lager, which meant she could drink for longer.

As her career soared, her mental health plummeted, she continued to drink and do drugs, even though she had become an ambassador for mental health. During her regular binges she'd black out - not be able to remember the next day what she'd said or done.

"I was always the one that just went that little bit too far. Then I would fill blackouts with the most unimaginably awful things that I'd done. My world, on a daily basis, felt like it was ending because of my behaviour."

Her husband tried to persuade her to stop but to no avail. A pivotal moment was when she went out on the lash with a superficial friend who had enough cocaine to keep them going for hours, knowing that she had a long car journey the next day with Harry and Edie, then four, to see her mother-in-law.

She awoke the next day at her friend's flat, 15 new messages on her phone from Harry, the last of which said that he and Edie had gone without her and that “we cannot go on like this; it is not fair for our daughter to grow up thinking this is normal”.

"It's tricky for family members because alcohol is the strongest thing in your life, that desire to drink, so you can spout off about how you love your husband and children but at the end of the day getting drunk is the most important thing," she says frankly.

Had she continued drinking, she believes it would have killed her.

"It doesn't bear thinking about what would have happened if I hadn't got sober," she says now. "I don't drink any more but I'm still an alcoholic.”

Gordon, now 40, spent 12 weeks in rehab.

"I was so lucky that I could afford to do that. It changed my life and I still see my counsellor once a week, even now, online during lockdown.

"When you get sober and you go into recovery and immerse yourself in the recovery community, you realise that this isn't a rarity, it's really common and yet it's very much still not spoken about," she continues.

"Alcohol is a legal drug. It's there in the shops, so at first there's the shame of, 'why can't I take it or leave it?' You hear the message, 'Drink responsibly', and I don't understand why I can't drink responsibly."

She believes telling her unexpurgated story will help her - and hopefully others - on the road to recovery.

Edie, who is now seven, doesn't remember Gordon as an addled alcoholic. "I tried my hardest to shield it and didn't drink until she was in bed. I know there will be things that will seem normal to her, like Mummy not reading her a story during part of her childhood. I don't talk to her about it. She knows I don't drink. She knows that I'm allergic to it.

"I hope that in 10 years' time when she might read the book, we'll be in a much better place in terms of mental health provision and the understanding of addiction and alcoholism."

The writer says it was easy to give up cocaine as she was only interested in it when she was drinking. Has she been close to falling off the wagon?

"The most important thing for me to remember is that I accept that a drink is never that far away. There's a bottle of red wine in our kitchen because my husband drinks, though not excessively. Every evening when he's cooking, he has one glass of beer. I don't get it, I don't understand, why doesn't he drink properly?

"Sometimes I'm envious when he has that drink but they're just thoughts and they pass. It's accepted that those thoughts will come."

Her mental health and life in general is so much better without booze, she enthuses.

"Life is much calmer now. It used to be periods of anxiety strung together with an occasional moment of relaxation, which was always provided by alcohol. Now it's just a series of very calm moments, with occasional anxiety.

"Sometimes I can't believe that I don't drink," she adds, almost in wonderment. "I've done it. And if I can do it, anyone can do it."

Glorious Rock Bottom by Bryony Gordon is published by Headline, priced £16.99 (ebook £7.99).