With only a fortnight left before the deadline, not even a third of companies, charities and public bodies have met their legal requirement to publish figures on their gender pay gaps. There was plenty of notice that all with more than 250 employees would need to do so. The slow pace indicates the low priority afforded to such concerns and, perhaps, a hope that embarrassing figures will be buried in a late rush of filings. It seems probable that many organisations will not comply, and it is unclear whether and how they will be punished. They should be.

The figures are not perfect. The refusal of law firms to include the earnings of (mostly male) partners, for example, produces technically accurate but misleading results. Nonetheless, the data published so far is powerful. Few if any women will be surprised that male colleagues outearn them per hour. But cold statistics have real force when they show disparities as stark as these: men at the UK wing of Goldman Sachs International earn more than twice the mean hourly pay of women. The impact is potentially reminiscent of #MeToo, if so far more muted. Such figures demonstrate to each woman that the problem is not an isolated case, but structural. They are not alone. Now they can prove it.

The journey from the 1970 Equal Pay Act to the 2010 Equalities Act represented a shift from the idea that individuals had a right to not be discriminated against, to the idea that the country should and would tackle discrimination. So while the figures may be helpful to women in lobbying for change – allowing them to show that comparable businesses have very different outcomes – it is up to their employers and their representatives to take action. But will they?

So far, many firms have boasted that they are committed to diversity (not committed enough, evidently) and that they pay the same for the same kind of work. This is not deserving of a gold star; equal pay is a legal requirement, in place for almost half a century. The shame is that it is not, in fact, being met in full. Worse, many companies – particularly those with striking pay gaps, such as fashion retailer Phase Eight (65%) and travel group Tui (56.9%) – seem to have missed the point. They say, in essence, that the gap exists because the senior jobs are dominated by men. This is not an explanation of the problem. It is the problem itself. The pattern of more women in low-paid jobs and fewer in high-paid jobs is seen in most organisations, across very different sectors; and it is why the figures showing employment rates per quartile are every bit as important as the hourly comparison. (The Guardian has an 11.3% mean hourly pay gap. This is lower than the current Office for National Statistics average, but it is not good enough and the aim is to reduce it further and to achieve 50-50 gender balance in the top half of the organisation within five years.)

Some women may simply leave organisations that do not reward them. Good for them; bad for the companies losing talent unnecessarily – but will their bosses realise this? The time for excuses and explanations is over. Real progress requires a broader response, with management, unions and politicians putting forward concrete plans to change the culture through measures such as blind CVs and unconscious-bias training; and setting specific, numerical, stretch targets. The equalities watchdog should call out those who do not report, and those whose figures are woeful, as well as offering breakdowns by region and sector. Much of the gap reflects an enduring tendency to discriminate on the basis of hours worked, and assume that top jobs can only performed in one way, by one person working full time – rarely possible if they have significant care commitments. MPs on the women and equalities select committee argue that increasing male involvement in family life, including through an extension of paid, ringfenced paternity leave, will be key.

The duty to report these figures is an annual one. There is a risk that their effect may dwindle in the years to come. But close analysis and publicity could make them more powerful, not less: it will become evident that some companies are closing the gap while others are making little or no progress. “The truth will set you free,” said Gloria Steinem. “But first, it will piss you off.” Prepare to get angry.