Working time in the United Kingdom is regulated in UK labour law in respect of holidays, daily breaks, night work and the maximum working day under the Working Time Regulations 1998. While the traditional mechanisms for ensuring a "fair day's wage for a fair day's work" is by collective agreement, since 1962 the UK created minimum statutory rights for every individual at work. The WTR 1998 follow the requirements of the Working Time Directive, which allowed an "opt out" from the maximum working week, set at 48 hours. Other reforms have included the 28 holiday minimum per year, 20 minute breaks for each six hours worked, and a maximum average of 8 hours work in a 24-hour period for night-workers (the average is usually calculated over 17 weeks, but it can be over a longer period of up to 52 weeks if the workers and the employer agree). History Eight-hour day Three-Day Week Flexitime Holidays The most concrete measure of the WTR 1998 is, following basic rights in international law, mandating a minimum period of 28 days, or four full weeks, in paid holidays for all workers each year (though this includes public holidays). There is no qualifying period for this, or any other working time right, because beyond the importance of the law in seeking to strike a balance between work and life, sufficient periods of rest and leisure are seen as a critical element of workers health and safety. Nor is it possible for an employer to give a worker "rolled up holiday pay", for instance an additional 12.5% in a wage bill, in lieu of taking actual holidays. The employer must make sure the worker does in fact take paid holidays, and if the worker has not done so and the job terminates, the employer must give an additional payment for the unused holiday entitlement. British Airways plc v Williams [2010] UKSC 16, [2010] 3 CMLR 19 Zentralbetriebsrat der Landeskrankenhäuser Tirols [2010] IRLR 631 (C-486/08) workers who move from full to part-time cannot lose their holiday entitlement. NHS Leeds v Larner (2011) EAT, Bean J held that the entitlement to paid annual leave under WTR 1998 rr 13 and 13A for a worker who was absent for the whole year because of sickness did not depend on the worker submitting a request for that annual leave before the end of the pay year. Stringer v Revenue and