Sleep-in workers: The National Minimum Wage applies only when awake for the purpose of working

As often seen in the care industry, workers on sleep-in shifts are contractually bound to be at or near their workplace overnight so that they can respond to an emergency.  However, they are permitted to sleep during their shifts until called upon. These sleep-in workers are keeping a listening ear out and are ready to respond, even as they sleep – but is that enough to say sleep-in workers are “working” for the purposes of calculating the National Minimum Wage (NMW)?

The Supreme Court in Royal Mencap Society v. Tomlinson-Blake unanimously disagreed and decided that the NMW is only payable for hours spent awake for the purpose of working.


Two cases with similar facts were heard together. A care support worker and a night care assistant were required to spend the night at or near their workplace on the basis that they could sleep for all or most of the night, but might have to wake up to tend to vulnerable adults or those in residential care. In practice, they rarely had to respond to emergencies or calls.

After more than a decade of service, both workers claimed against their respective employers for backdated pay. They argued that they were working or available to work during their entire sleep-in shifts and were therefore entitled to the NMW for every hour of those shifts, rather than the fixed pay or allowance they received. 

The Supreme Court decision

The Supreme Court rejected the claims.  It decided that neither was entitled to the NMW for all the hours of their sleep-in shifts.  The court found that, for NMW purposes, a worker is not working if he or she is not awake.  Indeed, to count towards the NMW calculation, it is not enough that the worker is awake – he or she must be awake for the purpose of working. That is, the sleep-in employee is only entitled to the NMW for time spent actively working.  In practice, that means the only part of the sleep-in shift which counts towards the NMW is the time spent actually responding to emergency calls.

What does this mean for employers?

This decision will likely be welcome news for many employers in the care industry as it means that they do not have to pay NMW arrears for their sleep-in workers.

The case brings to an end the lengthy litigation on NMW and sleeping time, and is helpful in clarifying which hours count towards the NMW calculations.  It does highlight the range of factors that employers should keep track of: the emergencies/calls each sleep-in worker responds to; what activity the worker was undertaking; the hours spent responding or carrying out work during sleep-in shifts; and so on.

What is this case not about?

Finally, it is worth pausing on what this case is not about:

  • While the focus of the case is on “working time”, this is working time for the purpose of the NMW Regulations.  It does not directly deal with working time for the purposes of the Working Time Regulations! These are distinct and use a different definition which accounts for what many might see as a contradiction between this case and the other recent Supreme Court decision about drivers using a ride-sharing app platform.  Those drivers were held to be working from the moment they logged on, but that was for the purposes of the Working Time Regulations.
  • Not every worker who is allowed to nap between tasks is a sleep-in worker. Workers who are “on call” or “on standby” may be in a different situation for NMW purposes.  Much will depend on what they are doing while on call.
  • The European Court of Justice recently held that standby time can amount to “working time” for the purposes of the EU Working Time Directive, if being on standby significantly constrains a worker’s ability to devote that time on standby to his/her interests, such as leisure activities. Multiple factors will be relevant in determining whether the constraint is significant, including the distance between a worker’s home and workplace. It is unclear how the UK’s position will develop in this post-Brexit era, and the distinction between a sleep-in worker and a worker on standby can be subtle and fact-sensitive. Therefore, it is worth asking your legal advisers to confirm where your workers – and their hours – stand.
  • The Supreme Court emphasised this case was heard before the coronavirus pandemic, and it does not consider how the NMW calculation will apply to the various stay-home measures brought on by the pandemic. This means that employers will have to continue to tread carefully when it comes to any pandemic-related working arrangements and keep an eye out for tribunal/court decisions for guidance.
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Victoria Middleditch

About Victoria Middleditch

Victoria is an employment lawyer in Dentons' London office. She provides support to businesses on the full range of employment law and human resources issues. Her experience includes advising on commercial transactions and re-organizations (including complex TUPE matters), employment disputes (both tribunal and civil court litigation), team moves, employment contracts and policies, bonus and commission schemes, and general day-to-day human resources issues.

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