The poet Philip Larkin, no friend of feminism, wondered why he let “the toad work / Squat on my life? … Six days of the week it soils / With its sickening poison – / Just for paying a few bills! That’s out of proportion.” Six days a week was even then rather old-fashioned: most of the industrial world had moved on to a five-day, 40-hour week by 1970, after more than a century of agitation, and there was an influential body of thought which held that further progress towards shorter working hours was inevitable as well as desirable.

What went wrong? Was the movement towards shorter working hours just part of a future that has largely disappeared, along with flying cars and world government? It hasn’t entirely vanished. In fact, it keeps reappearing: most recently with the announcement this month by the Wellcome Trust that it is going to explore the possibility of a four-day week for all employees; in France there is a 35-hour working week, but most people end up doing five hours’ poorly paid overtime anyway. The Swedish companies that investigated the possibilities of a six-hour working day earlier this century have for the most part retreated from them.

In large parts of the industrialising world, a 40-hour week is a distant dream; in the rich world the poorest workers find themselves working very long days whatever the law may say. But even some of the best-paid and most interesting jobs available now demand ridiculous commitments of time from anyone who wants to succeed at them. The treadmill only speeds up, wherever we find ourselves on it.

There is often a patronising note in discussions of a shorter working week: management gurus who suggest that the resulting free time be used so that employees can train for the triathlon, or polish up their meditation skills. Why should it not be spent resting, lolling around? Or at least in pursuits that do nothing for the CV at all: reading or playing games; for parents, spending ordinary time with children, since that is worth far more than “quality time” – which by definition comes in small doses. At the moment, some of these things are done by employees skiving off at their computers. Even the most interesting creative work is difficult to sustain in bursts longer than three or four hours. What comes after that is routine, however necessary.

The real problem is that working culture remains horribly gendered. The report that working full-time increases a mother’s stress hormones by up to 40% puts numbers on something we intuitively know. Flexibility helps working mothers a bit, but it does not reduce the endocrine load.

The culture of long working hours relies on unpaid caring work. All those 80-hour weeks are either done by men dependent on women to carry out domestic duties, especially childcare, or by women desperately trying to manage two full-time jobs, only one of which is outside the home and paid. This is a situation that probably suits some people. But it is certainly not what the majority of those trapped in it would choose if they had a real choice. Until the duties, and pleasures, of childcare are shared more fairly between the sexes, there will not be a move towards shorter working hours that really succeeds.