Carl v. The University of Sheffield

Factual and Procedural Background

This appeal concerns the interpretation of the Part Time Workers (Prevention of Less Favourable Treatment) Regulations 2000 (PTWR) in a dispute between Plaintiff and Company A before an Employment Tribunal. The Plaintiff, a part-time teacher in the Journalism Department at Company A, alleged less favourable treatment compared to a full-time comparator, Defendant, specifically regarding payment for preparation time. The Employment Tribunal found that the named comparator was not a true comparator and that no less favourable treatment existed compared to a hypothetical comparator. The Tribunal also dismissed a related claim under the Fixed Term Employees Regulations 2002, which is not appealed. The Plaintiff was previously determined to be an employee and thus a worker for the purposes of the claim.

Legal Issues Presented

1. Whether the Plaintiff is permitted to rely on a hypothetical comparator to show unlawful less favourable treatment under the PTWR.
2. Whether the Plaintiff must show that the less favourable treatment was solely on the ground of her part-time status.

Arguments of the Parties

Appellant's Arguments

• The Plaintiff contended that she could rely on a hypothetical comparator to establish less favourable treatment under the PTWR.
• The Plaintiff challenged the Employment Tribunal’s interpretation that the treatment must be solely on the ground of part-time status, arguing that it suffices if part-time status is an effective cause.
• The Plaintiff argued that the Employment Tribunal erred in rejecting the named comparator by focusing on differences rather than similarities.

Respondent's Arguments

• The Defendant submitted that the Plaintiff cannot rely on a hypothetical comparator under the PTWR, except in limited circumstances specified by regulations 3 and 4.
• The Defendant supported the Employment Tribunal’s reliance on prior case law that the treatment must be solely on the ground of part-time status.
• The Defendant argued that the named comparator was not a true comparator due to significant differences in role, qualifications, and work performed.

Table of Precedents Cited

Court's Reasoning and Analysis

The Court first examined whether the Plaintiff could rely on a hypothetical comparator under the PTWR. It noted that unlike discrimination statutes such as the Sex Discrimination Act or Race Relations Act, which explicitly allow comparison with hypothetical comparators, the PTWR’s definition of a comparable full-time worker does not include such a provision except in limited circumstances (regulations 3 and 4 relating to contract variations). The Court reviewed relevant ECJ and domestic case law, including Wippel, McMenemy, and Shamoon, and concluded that the PTWR does not generally permit reliance on hypothetical comparators.

Regarding causation, the Court considered the meaning of "on the ground that" within regulation 5(2)(a) PTWR. It rejected the Employment Tribunal’s narrow interpretation from Gibson requiring sole causation and instead adopted the broader test articulated in O'Neill and Sharma: the part-time status must be an effective and predominant cause of the less favourable treatment, but not necessarily the sole cause. This interpretation aligns with the Directive’s purpose and allows for more generous protection than the minimum required by EU law.

On the issue of comparator suitability, the Court upheld the Employment Tribunal’s finding that the named comparator was not comparable. The Tribunal properly considered differences in job role, qualifications, and work content under the regulatory definition of a comparable full-time worker. The Court distinguished this case from Matthews, where similarities outweighed differences, noting that here the differences justified rejecting the comparator.

Consequently, the Court held that the Plaintiff’s claim failed due to the absence of a true actual comparator and that the Plaintiff could not rely on a hypothetical comparator under the PTWR.

Holding and Implications

The Court’s final decision is DISMISSED as to the Plaintiff’s appeal and ALLOWED in part on the Defendant’s cross-appeal.

The Plaintiff is not permitted to rely on a hypothetical comparator under the PTWR except in the limited circumstances expressly provided by regulations 3 and 4. The Plaintiff must show less favourable treatment compared to an actual full-time comparator and that the treatment was on the ground that she was a part-time worker, where part-time status need only be an effective cause, not the sole cause. The Employment Tribunal’s finding that the named comparator was not comparable was upheld. As a result, the claim fails for lack of a valid comparator. No broader precedent beyond the interpretation of the PTWR and causation was established, and the ruling primarily affects the parties by upholding the dismissal of the Plaintiff’s claim.