A Norwegian financial trade union might be an unlikely mouthpiece for challengers of the global gender pay gap, but earlier this year it became just that. In an advertisement designed to highlight the company’s commitment to fairness in a sector still dogged by inequality, kids took part in a social experiment in which they were videoed being instructed to complete a simple task, for which they were rewarded with jars of sweets. Though all children completed the assignment to a similar standard, the boys were given more sweets than the girls. The adult running the experiment subsequently explained to the perplexed youngsters that the difference was down to their gender. Girls’ work, so the stoic message went, is worth less than boys’.

The children took issue, displaying a spectrum of emotions from confusion and annoyance to distress and resentment. It’s not fair, they unanimously agreed, a little shy at first and then more adamantly. And you’d be hard pressed to find an adult who publicly disagrees. But our workplaces are not a televised social experiment. We’re not kids who are refreshingly unconstrained by social filters that tell us what is acceptable. We’re being victimised by a culture of pay secrecy. It’s distasteful to talk about money, and that silence is wreaking havoc.

I’m writing this piece after a series of sleepless nights, tossing and turning, regretting my lack of courage when I signed on the dotted line, and hoping that future generations of women will be able to reap the benefits of the discussions we weren’t too cowardly to initiate.

I recently found out that a man sitting next to me in the office, who reports to me directly, is being paid £20,000 more than I earn annually. It might sound crass, but my reaction to this news has materialised as the five stages of grief. Grief, quite possibly, for my withering sense of self-worth.

At first comes denial. Surely this is a misunderstanding. Though we have our differences, my media mogul managers and I share a fundamental passion for progressiveness and – do I even have to say it? – an aversion to blatant discrimination. The organisation is meant to be famous for it.

Then anger strikes. It’s raw and blinding. I’d heard stories about such cases – reported them to death, in fact – but never had I felt so ridiculed. I’ve just had a baby. I’ve been negotiating my return to work. My desk neighbour is undeniably excellent at his job. He’s an ambitious and diligent employee with admittedly a few more years of experience than me. He’s a leader in his field, but when hired, I was deemed senior enough – amply mature, responsible and talented – to commission him, edit him and perform all the other far more mundane tasks of management.

Perhaps on account of his stellar reputation within the industry, a pay gap is justified, but the sheer size of this particular chasm has burned my ego to a crisp. The money at stake could buy me a car or cover rent in central London for months. Pertinently, it would even foot the bill of a large portion of childcare, for instance during that wonderful, exhausting first year of motherhood: that crucial make or break period after which I might be able to precariously leap back on to the speeding career treadmill, but only if I can nail the finances.

Right now I’m oscillating between the bargaining and depression phases. But I’ll never, ever reach acceptance.

In a way (and this could actually be the most tragic part), I blame myself. Everyone from Michelle Obama to Sheryl Sandberg has taught us about impostor syndrome. Now, I’m not sure we’ve learned anything. Had I let myself down when I was negotiating my salary, asking for a mere fraction more than the opening offer, out of fear that by demonstrating the most desirable trait of a professional woman – confidence in one’s own ability – I would scare them away? The patriarchy was probably lounging in its corner office, sucking on a fat cigar and chuckling at my innocent naivety.

My story is just one of a million tales. I will take action, but the punchline is that I can’t publicly put my name to my grievance. The media industry is smaller than you might think. If I earn the label of angry young female – a “nasty woman”, to borrow a phrase – I restrict my career prospects immeasurably. I literally can’t afford to be awkward. But this case has opened my eyes, and by sharing it I want to help others. Six out of 10 employees don’t know that they have a legal right to have conversations with colleagues about pay if they think they are being discriminated against because of their gender. That right should be a duty. A third of all workers don’t know that it’s illegal to pay women and men differently for the same or equivalent work.

Don’t let this rest. Have the courage to brave the conversation. No policies, regulations or initiatives will facilitate change if we allow employers to shirk their legal responsibility by shrouding salaries in secrecy. For the sake of my daughter and yours, enough is enough. Clutching their half-empty sweet jars, they would certainly tell us so.

• Anonymous is a media professional