Supreme Court allows part-time cab driver’s discrimination claim against company booking system access fee

About this case:

• Citation:
  [2026] UKSC 30
• Judgment:
  External link
• Court:
  UK Supreme Court
• Judge:
  Lady Simler

The appellant argued that a flat weekly fee levied on drivers by the respondent company regardless of weekly working hours amounted to less favourable treatment of part-time workers. That claim having been dismissed by the Court of Appeal, the appellant made further argument before the UK Supreme Court.

The appeal was heard by Lady Simler, Lord Lloyd-Jones, Lord Hamblen, Lord Leggatt and Lord Richards. With counsel for both parties acting pro bono, Tristan Jones KC and Aislinn Kelly-Lyth appeared for the appellant and Tom Mountford and Hugo Murphy for the respondent.

Less favourable treatment of part-time workers

In 2016, the appellant worked as a private hire driver for the respondent company. All drivers wishing to access the respondent’s booking system were required to pay a flat weekly fee of £148, known as the ‘circuit fee’, regardless of how many hours they worked per week. In contrast to some drivers who worked 60 or even 90 hours per week, the appellant averaged around 35 hours’ driving time – eight below the average weekly hours of the respondent’s drivers.

Noting the comparatively harsher effect of the circuit fee on those drivers working fewer hours, the appellant brought a claim before an employment tribunal. He alleged that the respondent’s policy amounted to less favourable treatment of part-time workers contrary to regulation 5 of the Part-Time Workers (Prevention of Less Favourable Treatment) Regulations 2000.

The right provided for by regulation 5 of the 2000 Regulations is subject to the caveat that it applies only if “(a) the treatment is on the ground that the worker is a part-time worker, and (b) the treatment is not justified on objective grounds”. Both the employment tribunal and the Court of Appeal dismissed the appellant’s claim, reasoning that his part-time status was not the sole ground for his less favourable treatment. The respondent, they considered, had an interest in earning revenue from the appellant’s use of their systems and may not, in any case, have had access to more sophisticated software allowing for differentiation between drivers working different numbers of hours. By consequence, the condition in paragraph (a) was not satisfied.

On appeal to the Supreme Court, the appellant argued that the phrase “on the ground that” was capable of applying to cases where the worker’s part-time status was an effective, but not the sole, cause of his less favourable treatment. By contrast, the respondent relied on the phrase “solely because” present in the framework agreement on part-time work put into effect by the European Union’s 1997 part-time work directive, which directive the 2000 Regulations seek to implement.

Effective, but not necessarily sole, cause

In a judgment with which her colleagues agreed, Lady Simler began by observing: “[I]t was inherent in the higher per hour fee paid by [the appellant] to work as a driver compared to his full-time comparator that there was at least some less favourable treatment on the ground of part-time worker status …[I]it is inherent in a provision which treats workers more or less favourably depending on the number of hours they work that it will treat a part-time worker less favourably than a full-time comparator. Accordingly, [the appellant’s] less favourable treatment compared with a person working 43.17 hours per week is attributable to his lower working hours or part-time status and this less favourable treatment at least is properly characterised as ‘on the ground’ that he was a part-time worker.”

Reviewing the authorities, she continued: “Before addressing the meaning of the causation test imposed by the 2000 Regulations, it is helpful to contextualise the phrase ‘on the ground that’ (and ‘on the grounds of’). Both are well-established in equality law at both European and domestic level … [B]y the time the 2000 Regulations were introduced, the meaning of the test imposed by the words ‘on the ground (or grounds) of’ in an anti-discrimination context was clear and authoritatively established. It meant that if the prohibited ground had a significant or substantial influence on or was an effective cause of the impugned treatment or outcome, direct discrimination would be made out. The prohibited ground did not have to be the main ground, still less the sole ground or reason for the treatment.”

Turning to consider the meaning of the phrase ‘solely because’ in the 1997 EU directive, Lady Simler noted: “We were not shown any judgment of the CJEU addressing the meaning and effect of the words ‘solely because’. Decisions by employers (and others) are frequently reached for more than one reason and, in this context particularly, it is easy to think of situations where an employer might point to budgetary (or other) constraints as another reason for the treatment if that would avoid the protection afforded by the Part-time Work Directive (and therefore avoid any need for objective justification). But the authorities we were shown … simply recite the same ‘sole’ ground phrase without saying what it means or indeed ruling out the possibility of a case being established despite the fact of more than one cause for the treatment alleged. It seems that the CJEU has not been invited to, and has not, decided any of these cases by pointing to some reason for the adoption of an impugned rule or treatment which is additional to part-time status, or by seeking to isolate a ‘sole’ reason for differential treatment when considering discrimination against part-time workers.”

Reasoning that there was no need to construe the 2000 Regulations in conformity to that directive, however, she continued: “Plainly, if regulations were made which apparently failed to enshrine in UK law the minimum standards required by a Directive, the courts would endeavour to construe the regulations so that those minimum standards were protected consistently with the UK’s international obligations. However, there was nothing to prevent the United Kingdom from providing protection which goes beyond those minimum standards. In the case of the 2000 Regulations, there is no doubt that the minimum requirements set by the Part-time Work Directive were satisfied. There is also no doubt that the Part-time Work Directive left open to member states the choice as to how the protection should be implemented and the possibility of introducing more favourable protection in doing so.”

Concluding her judgment, Lady Simler reasoned: “In my view, to require that the claimant’s status as a part-time worker be an effective cause of the less favourable treatment, even if not the sole cause of that treatment, is consistent both with the clear language of regulation 5(2) and with the protective purpose of this regulation. To hold otherwise is inconsistent with the approach standardly taken to questions of causation in discrimination cases and risks uncertainty and unreasonable outcomes … It seems to be counter to even the limited purpose of the 2000 Regulations to construe them as avoiding protection for treatment which inherently and necessarily disadvantages part-time workers (unless that treatment can be justified). The fact that not all part-timers are treated adversely should not mean that those who are cannot take proceedings for discrimination if being part-time is an effective cause (or reason) for their adverse treatment.”

The appeal was accordingly allowed.