Flexible working time relates to labour at varying hours or on varying days. The work is accomplished outside the normal working hours, the working time is abnormal or changes, or the working hours can vary. Countless schedules are possible with regard to flexible working time. An ILO definition within the context of labour flexibility is: flexibility in working time means changes in duration and scheduling of the working time of individuals or groups of workers in order to adapt operating time to the economic and organizational needs of the enterprise and to objective needs and subjective preferences of workers.
In the past century the workers' movement succeeded in reducing constantly both the daily and weekly working hours. Limits were fixed: often, eight hours a day and forty hours a week, ban on night and Sunday work. Since 1965 the average working time per employee in Europe has again gone down drastically. Parallel with this trend to a shorter working week, longer annual holidays have resulted in a shorter working time per employee on an annual basis. In Europe, the shortening of working time has led to a reflection on the traditional labour patterns and to the introduction of the currently accepted forms of working time organization. Both employers and workers (arguably those with a strong position on the labour market) are calling for greater work time liberalization.
In recent years, a large variety of labour relations have come into being in the European Union, with all kinds of working time constructions. The main developments are: (a) more flexibility in calculating overtime hours and in granting periods of rest; (b) calculation of the allowed average working time on the basis of shorter periods; (c) more flexibility in fixing the weekly working time; and (d) a less stringent ban on night and Sunday work. One new form of flexible working time is Europe is the flexible annual contract.
In most countries there is a strong difference between the legal maximum and the contractual working time – that which has been agreed in collective agreements. Most labour laws also provide for exceptions, allowing in some circumstances Sunday work, nine-hour working days and deviant working-time regulations for continuous production processes. In branches with clearly predictable peak and off-peak periods, such as in accountants' offices, staff may work more during the peak and less during the off-peak periods. Temporary and on-call employees may work a lot one week, the next hardly. The law has adjusted somewhat slowly to the practice; generally speaking, collective agreements seem to be more decisive for the (average) working time than the law, but there is considerable variation within branches. In Switzerland and Portugal the contractual working time is longer. In Sweden and the UK the real working time has grown longer, in contrast with other European countries. In Europe considerable differences in working hours exist between retail trade and industry. In England, Belgium, Spain and Portugal shops are open longer than in Germany. Generally, the extension of working hours is playing an important role in the private services sector.
Increasing flexibility of working time has far-reaching social consequences. The weekend, and particularly Sunday, is not only the time that no work is normally done. It is also the time for the family, for sports, for culture and for religious practice. Since many people do not work weekends, there is a possibility of organizing activities and upholding values. The spreading of Sunday work would cause this century-old structuring of time to change.