The European Court of Justice (ECJ) has set out the factors to be taken into account in order to decide when standby time should be counted as working time under the Working Time Directive (WTD).


In the two cases referred to the ECJ (DJ v Radiotelevizija Slovenija and RJ v Stadt Offenbach am Main) both claimants were required to carry out periods of standby duties. They were not required to spend their standby time at a particular location, but both had to meet particular response times that restricted where and how they could spend their standby time:

  • DJ was a specialist technician who had to be contactable and able to attend a site within 1 hour of a call. DJ lived more than an hour away from the sites he covered, so the required response time meant that he could not spend his standby time at home. Instead, he chose to stay in accommodation that his employer provided and so his leisure opportunities were limited. 
  • RJ was a Divisional Commander and fire fighter who had to be contactable and able to reach the town boundary of his place of work in uniform and in his service vehicle within 20 minutes of a call. The required response time meant that he had little choice but to remain at home during standby.

Both argued that the restrictions meant that the entire period of their standby time (not just the periods of any call outs) was working time under Article 2 of the Working Time Directive (WTD). The domestic courts each referred the question of interpretation to the ECJ.


Article 2 of the WTD provides that:

  • Working time means any period during which the worker is working, at the employer's disposal and carrying out their activity or duties, in accordance with national laws and/or practice.
  • Rest period means any period which is not working time.

The ECJ has previously held that an entire standby period would be working time where the worker:

  • was required to be physically present at a specific place so that they would be able to immediately provide their services, if required (SIMAP v Conselleria de Sanidad y Consume de la Generalidad Valenciana [2000] and Landeshauptstadt Kiel v Jaeger [2003]); or,
  • was not required to be physically present at a specific place, but the level of constraints placed upon them amounted to an objective and significant impact on their opportunity to pursue personal and social interests (i.e. more than simply being contactable) (Ville de Nivelles v Matzak [2018]).

The ECJ’s decision

The ECJ did not decide whether DJ or RJ’s standby time was working time; that is for the national courts to determine. Instead, the ECJ provided guidance for the national courts on the factors to take into account when assessing time under the WTD.

The ECJ made clear that an entire period of standby time would not necessarily be working time just because a worker had to be contactable and had a set response time; it can only be classified as ‘working time’ if the constraints imposed on the worker ‘objectively and very significantly’ affect the worker’s ability freely to manage the time during which their services are not required and to pursue their own interests.

Only the constraints that are imposed on the worker by law, by a collective agreement or by the employer are relevant. Any difficulties that the standby time may cause for the worker, which are the consequence of ‘natural factors or of his or her own free choice’, may not be taken into account (for example, the fact that DJ’s home was far away from the workplace and that he had to stay in a place that had limited leisure opportunities were irrelevant factors).

The ECJ set out a number of relevant factors that should be taken into account by when deciding whether standby time is working time. Those factors are:

  • The required response time during standby
  • The frequency of the call outs during standby time
  • The length of time of each call out

Standby time with short response requirements, frequent call outs and “non-negligible” periods of activity during a call out, will, in principle, be working time. Any time that is not classified as working time must by default amount to a rest period.

However, the ECJ confirmed that any assessment of time under the WTD does not override the employer’s duty to protect the health and safety of their workers. Therefore, employers cannot rely on standby time not being working time (and so, by default, being a rest period) to require workers to be on standby for very long and/or very frequent periods if that would create a risk to the worker’s health or safety.

What to take away

These Judgments provide further helpful guidance to employers on how to assess standby time where the worker does not have to be physically present at work but does have to be contactable and responsive. We recommend that employers review their “off-site” standby and on-call practices with reference to the relevant factors set out by the ECJ in order to identify and address any risks in terms of 1) whether that time may be assessed as working time under the WTD and, 2) the impact of standby time that is undertaken on workers’ health and safety (regardless of any WTD assessment).  

How Capsticks can help

Capsticks has significant experience of supporting employers on working time issues (by drafting policies, contracts and delivering training to employees at all levels) and also to deal with any complaints that may arise (by conducting investigations, supporting decision makers and HR, and defending any employment tribunal claims).

For further information on how we might assist your organisation, please contact Victoria Watson, Alistair Kernohan or Chloe Edwards.