Augustine v Data Cars Limited

Under regulation 5(2)(a) of the Part-Time Workers (Prevention of Less Favourable Treatment) Regulations 2000, part-time status need not be the sole cause of less favourable treatment. It is sufficient that the status was an effective cause, or had a significant or substantial influence on the treatment.

The existence of another cause does not prevent the right from arising. It may instead be relevant to objective justification or the assessment of compensation. Domestic implementing legislation need not be restricted to the minimum protection in an EU directive where the directive permits more favourable national protection and the domestic wording establishes a wider right.

Augustine v Data Cars Limited concerned a private hire driver who worked part-time and paid the same fixed weekly fee for access to his employer’s booking system as full-time drivers. The arrangement caused him to pay more per working hour and retain a smaller proportion of his earnings than his full-time comparator.

The employment tribunal dismissed his claim under regulation 5 of the Part-Time Workers (Prevention of Less Favourable Treatment) Regulations 2000. The Employment Appeal Tribunal held that there was less favourable treatment and that part-time status was an effective cause, but considered itself bound by Scottish authority requiring part-time status to be the sole cause: [2024] EAT 117; [2025] ICR 19.

By a majority, the Court of Appeal agreed that the sole-cause approach was wrong but likewise considered itself bound by that authority and dismissed the appeal: [2025] EWCA Civ 658; [2025] ICR 1404. The central issue was whether regulation 5(2)(a) requires part-time status to be the sole ground for less favourable treatment or merely an effective cause of it.

1. Appeal allowed unanimously. Lady Simler delivered the judgment, with which Lord Lloyd-Jones, Lord Hamblen, Lord Leggatt and Lord Richards agreed. Regulation 5(2)(a) of the Part-Time Workers (Prevention of Less Favourable Treatment) Regulations 2000 prohibits less favourable treatment where part-time status is an effective cause of that treatment. It need not be the sole cause.

2. The expression “on the ground that” had an established meaning in discrimination law when the Regulations were made. A prohibited characteristic is causative where it consciously or subconsciously influences the treatment, or where the criterion applied is inherently tied to that characteristic. The characteristic may be one of several causes. It is enough that it had a significant or substantial influence on the outcome. Motive and intention are immaterial.

3. The meaning of “solely because” in clause 4.1 of the Framework Agreement on part-time work did not have to be decided. Existing CJEU decisions had not determined whether those words exclude all cases involving multiple causes. Even assuming that clause 4.1 imposes a narrower test, clause 6.1 allowed member states to introduce more favourable protection.

4. There was no imperative to give the domestic Regulations a conforming construction which imported that assumed limitation. Section 19 of the Employment Relations Act 1999 conferred a broad, free-standing power to protect part-time workers. The Secretary of State omitted “solely because” and instead selected language whose established domestic meaning embodied effective causation. The principle stated in United States of America v Nolan [2015] UKSC 63 applied: where a directive permits wider national protection, conformity does not require domestic legislation to remain at the directive’s minimum level.

5. The use of “only” in regulation 5(2) requires both causation and the absence of objective justification; grammatically, it does not make part-time status the sole cause. The singular “ground” identifies the single protected ground of part-time status. The differing references to reasons and grounds elsewhere in the Regulations do not alter that conclusion.

6. Applying the pro rata principle, the fixed weekly fee treated the appellant less favourably because he paid more per hour and retained a smaller proportion of his earnings than a comparable full-time driver. That disadvantage was inherently attributable, at least in part, to his part-time status. Other causes may be relevant to objective justification or to compensation assessed on a just and equitable basis, but they do not prevent the right from arising. The sole-cause reasoning in McMenemy v Capita Business Services Ltd [2007] CSIH 25 was disapproved, although its result was correct on its facts.

1. United Kingdom Supreme Court: The court unanimously allowed the appeal and held that part-time status need only be an effective cause of the less favourable treatment: [2026] UKSC 30 .
2. Court of Appeal: By a majority, the court regarded the sole-cause approach as wrong but considered itself bound by Scottish authority and dismissed the appeal. Elisabeth Laing LJ considered the sole-cause approach correct: [2025] EWCA Civ 658 ; [2025] ICR 1404 .
3. Employment Appeal Tribunal: The tribunal held that the fixed fee produced less favourable treatment and that part-time status was an effective cause, but considered itself bound to apply the sole-ground test and dismissed the appeal: [2024] EAT 117 ; [2025] ICR 19 .
4. Employment tribunal: The tribunal dismissed the claim. It found no less favourable treatment and held alternatively that the claim failed because part-time status was not the sole ground for any disadvantage.