Whenever Ministers or Conservative politicians are asked for an example of the sort of powers they want to repatriate from the European Union, they reach, first and foremost, for workers' rights and, specifically, the Working Time Directive. And yet, the social dimension is an indispensable element of the European single market. It is what makes it palatable for trade unions and the people we represent.

This directive is, of course, a long-running sore for the Conservative Party, who opposed the Directive when it was initially proposed in the 1990s and even took the issue to the European Court of Justice on the grounds that it wasn't a health and safety measure (although even their own occupational health adviser told them categorically that it was and that they were wasting their time.) 

There is compelling evidence to show that regularly working long hours is associated with an increased risk of developing heart disease, stress, depression and diabetes. One of the biggest pieces of research, the Whitehall Cohort Study, has followed more than 10,000 civil servants since the 1980s. Indeed, a recent study from the University of Tel Aviv suggested that excessive working time and burnout were more likely than smoking cigarettes to generate heart disease.

The Working Time Directive addresses two main issues: a right to paid holidays and rest breaks, and control of the length of the working week. It is difficult to find anyone now ready to demand that workers should be stripped of the former. And on the latter, the Directive - only enforced in the UK when someone complains, unlike most health and safety law - is one of the most flexible on the statute books, allowing averaging, exceptions, negotiated exemptions and the infamous opt-out.