A maximum working week provides protection for workers.  In the Universal Declaration of Human Rights in article 23 “Everyone has the right to work… to just and favourable conditions of work” and article 24 “Everyone has the right to rest and leisure, including reasonable limitation of working hours and periodic holidays with pay”1 both relate to a fundamental freedom from being forced to work too hard. Working for too many hours per week can affect health, wellbeing and productivity over the medium to longer term. In extremis, as we can see in the “karoshi” phenomenon in Japan, people can work themselves to an early grave.2  Even in less extreme examples, we can see health issues affecting productivity and causing medical problems which require paying to treat. The WHO estimates that work related stress costs $300bn p.a. in the US, to take one example.3  It goes without saying that all this avoidable stress and medical trouble needs paying for. That the businesses themselves manage to push those costs onto wider society or the state doesn’t make those costs go anywhere from the point of view of an economy as a whole. Therefore a maximum working week prevents business from externalising costs to others.  1 United Nations, Universal Declaration of Human Rights, 1948