Imagine turning up to work every day knowing the person sitting opposite you is doing everything in their power to push you out of your job.

That was the shocking reality for Naomi Joy, a 30-year-old former PR director from London, who witnessed and experienced 'toxic femininity' throughout her career.

She reveals one female colleague in her thirties once declared everyone in the office 'hated her', while another tricked her into making a mistake so that she would be favourite for a promotion.

It eventually led to Naomi quitting her job and penning The Liars, a psychological thriller about two rivals competing for a promotion, inspired by her own shocking experience.

While researching her book, she conducted a survey of 1,000 employed British women and found more than half claimed to have been sabotaged at work by another member of the so-called sisterhood, while more than a third (37 per cent) said they'd actually felt scared or threatened by a female colleague.

Here Naomi tells FEMAIL how she coped with all-out office war - and how you can attempt to break through the 'sisterhood ceiling'...

Naomi Joy, a 30-year-old former PR director from London, says she witnessed and experienced 'toxic femininity' throughout her career

It had been building for a while. I'd been walking on eggshells for months, trying not to provoke one particular female colleague prone to passive aggression and making snide remarks.

In her early thirties, bright and energetic, she had seemed supportive at first, keen to be friends in the chic PR agency where we worked.

Now she'd finally come out with it: 'Everyone in this office hates you. Everyone wants you to leave.' Furious, I remember clenching my hands so hard the nails punctured the skin on my hands, drawing blood.

And what did I do next? Well, nothing of course - instead I tried to placate her, like so many women would have done in my place. Yet something changed forever that afternoon. It was the beginning of the end of a life lived in the shadow of other women's toxic femininity.

I thought I'd learned my lesson about female rivalry at the very start of my career when, as a young intern, I was fortunate enough to land a dream full-time job at PR and events agency.

Naomi reveals one female colleague in her thirties once declared everyone in the office 'hated her', while another tricked her into making a mistake so that she would be favourite for a promotion

The boss - a brilliant, rather fierce woman with high-arched eyebrows and dark-red lips - had decided to give me the position, much to the chagrin of the other female intern who would have to leave.

This girl, who I'll call Tara*, said nothing to my face - but then she didn't need to. Instead she made sure I had the wrong information for the following day's photoshoot, while I was too naive to bother checking.

I spent the following morning dashing along Oxford Street hunting for pairs of gold designer heels. Shoeboxes were piled high in my arms as, eyes watering as I stuffed receipts from Manolo Blahnik, Louboutin and Jimmy Choo into my purse. I hadn't been given a credit card as juniors were expected to stomach expenses like this and wait a month to be reimbursed. I couldn't afford it.

I got to the shoot at lunchtime as instructed, bright red and sweating, only to be met with a single brusque question: 'Where have you been?'

The Liars by Naomi Joy, published by Aria, is available to buy in paperback and e-book from Amazon

I looked around to see the cameras were packed up, blow-up palm-tree props deflated, a pair of bright-gold designer heels flung to one side.

Tara stood smugly across the room, hand covering her mouth, jaw dropped with faux-shock. I handed the shoes to the woman who had offered me the job, stuttering an explanation.

'What are these?' she snapped. 'The shoot finished an hour ago. There was no one on hand to fetch coffees. I had to do it myself!'

Tara got the job instead of me - a sign of things to come.

Millions will recognise what I'm talking about - that world of women who flash you a broad smile as they turn on their computers in the morning, teeth still on show as they huddle into their screens while angrily plotting your demise in secretive emails.

These are the women who actively block your path to success if they deem you a threat; women who, in my experience, create a ceiling far harder to break than a glass one. And, much as it pains me to say it, they exist in offices everywhere.

I conducted my own survey of 1,000 women in full-time employment in Britain, and a troubling 58 per cent of them told me that they had at some point been sabotaged at work by another member of the so-called sisterhood. There was no bias in terms of age, location or wealth.

Naomi told how she experienced a sisterhood ceiling throughout her career in PR and marketing

My second job took me to some of London's most exciting red-carpet occasions. I held vast black umbrellas over the heads of celebrities. I set up events with Olympic athletes and worked on publicity campaigns that made a real difference to people's lives.

The culture was much better. Even so, there was one woman who, when my promotion was announced, took me to one side to say I hadn't deserved it.

'I had to wait a year to be promoted, you only had to wait nine months,' she said. 'It's not fair.'

Her disruption became systematic. She blamed her mistakes on me. She blocked my chances to work on more important projects, spreading rumours that I would probably leave the company soon. This woman, by the way, was supposed to be my mentor - and, despite everything, I wanted her to like me.

She wasn't the only one. There was a senior colleague who quite incorrectly pointed the finger of blame at me in a crisis meeting. 'You understand why I had to do that, right?' she said afterwards.

A survey of 1,000 employed British women and found more than half claimed to have been sabotaged at work by another member of the so-called sisterhood, while more than a third (37 per cent) said they'd actually felt scared or threatened by a female colleague. Pictured: stock image

'I'm the head of this project, if they think I'd f****d up we would have been fired. Thanks for understanding, hun. You're the best.'

I put it down to being junior, telling myself that my brilliant female bosses - and they were brilliant - wouldn't want to hear about such petty problems. My female friends agreed. This was just the industry we're in, we said. Things would get better as we moved through the ranks.

They didn't. The higher I climbed, the more toxic the female rivalry became.

Top PR offices have a few things in common. There are the white walls splashed with vibrant art, the model receptionists, the sound of manicured nails typing furiously on sleek silver keyboards. It's all rather Devil Wears Prada - in more ways than one.

I was 24 when I landed a job at a boutique PR agency in central London, working with a range of clients in health and beauty.

Naomi said she also had the finger of blame pointed at her for her boss' mistake, who admitted she was in the wrong but let her take the rap

One of my new colleagues stood out among the rest. Around my age, she had the confidence to be brusque with juniors, seniors and clients alike. I liked her. She knew her stuff and she was great at her job. I wanted her to like me.

For a while, everything was harmonious until, with the annual review of salaries on promotions on the horizon, things began to change.

She started ignoring my emails. She wouldn't take part in team meetings if she thought I'd be running them. In fact, she avoided working with me on anything at all.

She started referring to herself as my senior. She tried to find out how much money I was earning per year. She even told a colleague she was keeping a log of the things I did in my free time - and that she was determined to make sure I couldn't get ahead of her in any regard.

I had laser eye surgery; she bought a new pair of glasses and had a make-over. I had my teeth whitened; she went to the same clinic to have hers done a week later. Her competition with me was fierce and about so much more than work.

Evelyn Cotter, a career coach who founded SEVEN Career Coaching, told me that female clients routinely claim they have been undermined by other women

Then, after nearly a year, came that derisive outburst - the claim that 'everyone hates me'. Childish, yet devastating.

I didn't leave the agency right away. Instead I started writing about what I'd seen and felt – the things that happened to me in offices in London and California. About the repeating pattern of women turning against each other in order to get ahead.

Six months later I had a literary agent and a three-book deal. My first novel, The Liars, launched a few weeks ago.

It follows the stories of two women – Ava and Jade – each with their own touch of toxicity, who are fighting for the same promotion. Jade is more experienced, but Ava's connections with those in powerful positions make her the frontrunner for the role. To make matters worse, they share a secret - one they know will ruin them both if told.

What is the sisterhood ceiling? According to an academic study in 2016, one of the biggest barriers to female career advancement is other women. The paper, published in the Journal of Personality and Social Psychology, concludes that women are more likely to fall out with female colleagues whom they suspect of trying to elbow them aside on the career ladder than they would with men. Lead author Sun Young Lee, an assistant professor at the UCL School of Management, said the findings suggest standard career structures which encourage people to compete for promotion are disadvantageous to women. 'As a woman who has worked across the world, I've long observed that women take competition with other women much more personally than men take competition with other men - my research provides support to such an observation,' Dr Lee said. 'Bosses need to be aware that competitive career structures that are effective to men may be detrimental to women. 'At the same time, women should be aware that taking competition too seriously could be holding them back from leadership positions.' Advertisement

The response has been extraordinary. Close friends have shared their own experience of female rivalry at work. Readers have been in touch to say their lives have been turned upside down by female bullying.

Researchers at University College London have explained the phenomenon as 'The Sisterhood Ceiling', concluding that, while men are buoyed by competition, women report negative emotions - but only when competing with other females.

The result, they suggest, is that some struggle to maintain healthy relationships and adopt a cut-throat approach to other women instead.

Evelyn Cotter, a career coach who founded SEVEN Career Coaching, told me that female clients routinely claim they have been undermined by other women.

'I've been consistently shocked in my career and business to see female rivalry and jealousy as the norm,' she said. 'Sadly, as women we exist in a world designed by generations of men.

'The office is a heightened masculine environment and a system that is not set up for women to flourish and thrive, unless they develop more masculine traits, and, even then, success is not easy.

'Women subconsciously understand that they start on the back foot. This breeds insecurity which, in turn, breeds fear.'

So much of this rings true from my own experience in the office - all that fury heaped on women who dare to 'get ahead'. I see my own shortcomings, too, because in my heart I favour 'niceness' and cooperation.

Evelyn offers some advice if you are a woman facing this problem: 'As difficult as it is, take a step back, tap into those wonderful female traits like empathy, high emotional intelligence and awareness of others, and really look at why this person is behaving like this.

'If you can get into a conversation with her where you can both speak on an adult basis, you could ask how, instead of using our energy against each other, we could support each other.'

Easier said than done, I know. But however many obstacles we face in the office, toxic femininity shouldn't be one of them.

The Liars by Naomi Joy, published by Aria, is available to buy in paperback and e-book from Amazon.

*Names have been changed.