The Supreme Court has confirmed that part-time workers do not need to show that they were treated less favourably solely because they worked part-time. Instead, it is sufficient for a worker to show that their part-time status was an effective cause of the treatment, even if there were other contributing factors. This change lowers the bar for claims under the Part-Time Workers Regulations 2000 (PTWR). It means taking a fresh look at how your policies affect part-time staff and considering carefully whether you can objectively justify any difference in treatment.
Augustine v Data Cars Ltd
Mr Augustine worked as a part-time private hire driver for Data Cars Ltd. Data Cars required all drivers, regardless of whether they worked full-time or part-time, to pay the same weekly “circuit fee” of £148 to access its booking system.
Mr Augustine argued that charging the same fixed fee meant that, in practice, he paid a much higher fee per hour worked than a comparable full-time driver. He brought a claim in the employment tribunal (ET), contending that this amounted to less favourable treatment because he worked part-time, contrary to the PTWR.
The ET rejected the claim. Although it accepted that both full-time and part-time drivers were charged the same fee, it held that the fee was not charged solely because Mr Augustine was a part-time worker. The Employment Appeal Tribunal rejected Mr Augustine’s appeal, considering itself bound by an earlier Scottish case (McMenemy v Capita Business Services Ltd), albeit it considered McMenemy was wrongly decided.
The Court of Appeal also dismissed the appeal. The majority expressed doubts about whether McMenemy had been correctly decided but regarded themselves as bound to follow it. The Court of Appeal granted permission to appeal so that the Supreme Court could resolve the issue across the UK.
The Supreme Court’s decision
The Supreme Court unanimously allowed the appeal. It held that the wording of the PTWR differs from the European Framework Agreement by protecting workers where the treatment is “on the ground that” they are part-time, rather than “solely because” they are part-time.
The court found this difference was deliberate and reflects more closely the approach taken in discrimination claims where a protected characteristic, such as disability or sex, need only be part of the reason for the treatment, not the only reason. It also confirmed that the government was entitled to provide greater protection than the minimum required under European law.
As a result, a claimant only needs to show that their part-time status was an effective cause of the less favourable treatment, even if there were other contributing factors. In this case, the Supreme Court considered that the other reasons Data Cars put forward for Mr Augstine’s less favourable treatment were better characterised as possible justification arguments. Data Cars did not seek to justify its treatment of Mr Augustine before the ET (or on appeal).
Why this matters for employers
The decision makes it easier for part-time workers bringing claims to establish the necessary connection between their part-time status and less favourable treatment. Employers can no longer argue that a claim fails simply because part-time status was not the sole reason for the treatment.
Instead, employment tribunals will consider whether part-time status was an effective cause. This aligns the approach under the PTWR more closely with the approach already used in other discrimination cases. It is likely to mean a greater practical emphasis on whether the employer can objectively justify the difference in treatment.
Key takeaways
With the bar for claims now lower, employers should consider whether apparently neutral policies have a less favourable effect on part-time workers and, if so, whether part-time status plays an effective part in producing that outcome.
- Audit fixed charges and thresholds: Identify any policies where part-time and full-time workers are charged the same flat fee (such as flat-rate charges, minimum-hours requirements and other fixed thresholds). Consider whether these have a disproportionate impact on part-timers.
- Review pay and benefits structures: Check bonus arrangements, benefits and eligibility criteria (such as minimum hours to qualify for a bonus) for provisions that may result in less favourable treatment of part-time staff.
- Document your justification: Where different treatment is linked to part-time status, ensure you have a clear, documented business reason that would satisfy the objective justification defence. This means being able to show that the treatment is a proportionate means of achieving a legitimate aim.
- Briefmanagers: Make sure line managers understand that “part-time status was only one factor” is no longer a complete defence.
The decision provides a useful prompt to review arrangements affecting part-time workers. Where part-time status contributes materially to less favourable treatment, it is important to be ready to explain and evidence any objective justification.
