Figures show that stricter labour laws introduced in 1998 have seen the number of UK employees working more than 48 hours a week fall by around half a million from 3,992,000 to 3,494,000, according to the union’s figures.
But how does the average working week in Britain compare to its peers across Europe and the developed world?
This map below shows the average working week across various countries, taking the latest data from the OECD, which applies to 2014.
Countries in western Europe have some of the best working hours.
In Germany, employees work an average of 34.5 hours a week, while in neighbouring Switzerland the average working week is 34.4 hours.
This compares to an average of 49 hours a week worked in Turkey.
Looking at other countries across the OECD, Mexico and Colombia also have long working weeks, with average hours topping 40 hours in both. South Africa and South Korea also have long labour hours.
In terms of overall working conditions, France is widely recognised as the best in Europe. Not only does it have a relatively short working week – at 36.1 hours – but it also has one of the most generous holiday packages in Europe. French workers are entitled to 30 days a year. This compares to 28 days in Britain, which can include Bank Holidays.
In Britain, workers average around 36.5 hours a week. This has dropped from 37.1 hours a week in 2000, which could take into account digital developments that mean more people are working from home.