The Employment Appeal Tribunal (EAT) has confirmed that for there to be a breach of the, Part-Time Workers (Less Favourable Treatment) Regulations 2000 (SI 2000/1551) a claimant’s part-time status must be the sole reason for the less favourable treatment.
In the case of Mireku v London Underground Ltd EAT 57 (29 April 2025), Mr. Mireku alleged that he had been treated less favourably in relation to the cancellation of overtime, contrary to the PTW Regulations. An employment tribunal rejected his claim, finding that the overtime was cancelled for reasons not connected to his part-time status. Mr. Mireku appealed, arguing that the tribunal had applied the wrong causation test.
The EAT acknowledged conflicting authorities on the question of causation under the PTW Regulations. While the Court of Session, Inner House had found that part-time status must be the sole reason for less favourable treatment (McMenemy v Capita Business Services Ltd SC 492), the EAT decisions in Sharma v Manchester City Council ICR 623 and Carl v University of Sheffield ICR 1286 considered the test to be whether part-time status was an “effective and predominant cause” of the treatment.
However, in Augustine v Data Cars Ltd EAT 117, Eady P had comprehensively reviewed all these earlier authorities. While she expressed a preference for the “effective and predominant cause” test, she reluctantly considered herself bound by the decision in McMenemy. On this specific question of precedent, there was no conflicting authority. Therefore, applying Lock v British Gas Trading Ltd EWCA Civ 983, it was inappropriate for the EAT to depart from Augustine.
In any event, the EAT noted that Mr. Mireku’s case was bound to fail regardless of the approach to causation, as the comparators he relied on were not comparable full-time workers, contrary to the PTW Regulations.
