Reference periods for averaging working time

Where working time limits apply as averages rather than absolute limits (like the 48-hour week under the WTR regulations, or working time limits for night workers other than those dealing with special hazards) a reference period is needed for the calculation. A longer reference period allows more weeks of the year during which working time can exceed the average limit (providing that it is balanced by weeks when working time is below the limit).

Under the main WTR regulations the standard reference period for the 48-hour week is successive periods of 17 weeks (where there is a “relevant agreement” to this effect, see chapter 3) or otherwise a rolling period, that is, any period of 17 weeks (WTR regulation 4). Where a worker has worked for the employer for less than 17 weeks, the reference period is the period elapsed since s/he started work for the employer.

The distinction between successive and rolling reference periods could be important where workloads are spread unevenly. If an employer prefers a successive reference period arrangement, that could provide the basis for negotiations even if an extended reference period is not required.

Under NHS Agenda for Change terms and conditions, unless it is agreed with locally recognised unions to the contrary, the averaging reference period … is the 17 weeks immediately preceding each day in the course of a worker’s employment.