Take two people, who have exactly the same skills and work exactly the same hours.
One gets paid more than the other, for no other reason aside from the fact that they have a different set of reproductive parts. Does that sound fair, or does that sound like the messed up premise from some totalitarian sci-fi novel?
This is what the equal pay argument is reduced to in this supposedly democratic, free-thinking world of ours . Women get paid less than men for the simple fact that they are women, nothing more, nothing less.
They now make up 47% of the UK workforce, but statistically they still earn 15.7% less than men per year.
On average, for every pound a man makes, a woman will only earn 80p. Currently, the average woman earns £2.53 less than the average man per hour. What the hell is that still about?
Equal Pay Day aims to tackle gender inequality faced by working women, by asking why women are paid less than men for the same work and challenging the fact that there are still more men in high powered jobs than women.
Beyoncé, just one of the celebrities who supports equal pay for women
Despite feminism's best efforts, the gender pay gap has actually got worse in the last year. Women will effectively work three days more for free than they did in 2013.
Vice-president of Equal Pay Day and EU commissioner for justice, fundamental rights and citizenship Viviane Reding, said: "European Equal Pay Day reminds us of the days and hours that women have been working 'for free' since 1 January.
"The principle of equal pay for equal work is written in the EU Treaties since 1957. It is high time that it is put in practice everywhere.
"I am grateful to the global Equal Pay Campaign Day for helping us to make this happen. Let us work together to deliver results not only on Equal Pay Days, but on all 365 days a year!"
Here are just some of the high profile women and men who have spoken up for equal pay....
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Jo Swinson, minister for women and equalities, told the Huffington Post UK: “More than forty years on from the Equal Pay Act, it is unacceptable that women still earn less than men.
“Most businesses do not intentionally discriminate against women on pay, but many are surprised by the result when they do the analysis.
“We must continue to use all avenues possible to reduce the gender pay gap, and I look forward to seeing how this is put into practice by businesses. Companies are to blame for the gender pay gap, not women.”