Did you think that it was only in Victorian England that debtors were forced into the workhouse? Think again. This week a leaked letter revealed that Greece's eurozone creditors are demanding a six-day week as a condition of the latest bailout.

Of all the far-out ideas for solving the Greek crisis, this one surely takes the biscuit. First, it is completely unenforceable. Second, those Greeks in full-time employment already work the longest hours in the European Union. Finally, how does the troika (the EU, International Monetary Fund and European Central Bank) propose to provide work for the 25% of Greeks unemployed? And yet, as preposterous as the demand may sound, it needs to be taken seriously – not least as a symptom of a growing belief that Europeans have to work longer and harder to recover prosperity.

The reduction of the working week was one of the great achievements of 20th-century social democracy. A labourer in mid-Victorian Britain could expect to work 60 hours a week – 10 hours a day, six days a week – from adolescence till death. Sundays alone were left free for chapel or gin. The early trade union movement campaigned vigorously against this regime with the slogan "Eight hours labour, eight hours recreation, eight hours rest". Its efforts bore fruit. By 1930, weekly hours in Britain had sunk to 47; by 1980, they were down to 40. Sociologists talked of the coming "end of work" and wondered with vague apprehension how the vacant hours would be occupied.

Then something strange happened. Some time around 1980, working hours in most western nations stopped falling. In Britain and the US, they actually started rising again, especially among the rich. This new trend coincided, not accidentally, with the deregulation of markets, the smashing of union power and the growth of income inequality. The world reverted to the earlier, more brutal form of capitalism characterised by John Stuart Mill as "trampling, crushing, elbowing, and treading on each other's heels".

The free-market right looks favourably upon the revival of work. Indeed, some say it has not gone far enough. "The British are among the worst idlers in the world," claims Britannia Unchained, a recent polemic by five young Tory radicals. "We work among the lowest hours, we retire early and our productivity is poor." The authors conclude with a paean to "the lost virtue of hard graft", now exemplified by the Asian tigers.

The pro-work brigade offer us two arguments. The first is economic: we need to work harder in order to keep pace with the industrious Asians and support our growing population of retirees. The second is psychological: work is enjoyable, or at any rate good for us. If we worked only 20 hours a week, American judge Richard Posner argued recently (in a review of our book), we would "brawl, steal, overeat, drink and sleep late." Slackers need the discipline of work to stay on the straight and narrow.

Neither argument is convincing. The first ignores the fact that prosperity is connected to productivity, not hours of work. The Germans have the most successful economy in Europe despite working shorter hours than the hapless Greeks. Hardly any production was lost in the two months when Edward Heath put Britain on a three-day week in 1974. Many British office workers fill out their long hours with important-sounding but factitious activity: video-conferencing, PowerPoint presentations, "brain-storming" sessions. Remember Parkinson's law: work always expands to fill the time available.

The second argument is a counsel of despair. It pictures us as so incapable of making creative use of our time that we need others to organise it for us. Insofar as this is true, it is an indictment of our civilisation. "There was formerly a capacity for light-heartedness and play which has been to some extent inhibited by the cult of efficiency," wrote Bertrand Russell in his 1932 essay, In Praise of Idleness.

We have lost the arts of leisure, and so face a stark choice of work or dissipation. Our predicament is that of the world-weary French poet Baudelaire, who wrote: "One must work, if not from taste, then at least from despair. For to reduce everything to a single truth, work is less boring than pleasure."

In 1929 the economist John Maynard Keynes looked forward to a world without work, in which "we shall once more value ends above means and prefer the good to the useful". Yet all we can offer our children is insecurity and hard graft. Keynes found his social ideal in the writings of poets and philosophers. How ironic that already wealthy western societies find theirs in the sweatshops of China and the workhouses of Victorian England.