In Roddis v. Sheffield Hallam University the EAT held a worker employed under an associate lecturer's contract of employment described by the Employment Tribunal as a zero-hours contract, was employed under the same type of contract as a lecturer on a full-time contract for the purposes of Regulation 2(2) and 2(4)(a)(i) Part-time Workers (Prevention of Less Favourable Treatment) Regulations 2000.

The Claimant was employed as an associate lecturer by the University, commencing employment on 30 January 2006. He was employed under a zero hours contract which stated that his hours of work would vary according to the workload of the University's business; that the University was under no obligation to provide any work or to provide a minimum number of hours in any day or week; and that offers of work would be made at least one month prior to commencement of the relevant academic year or semester. He received over 30 SHU 5a forms (offers of work) in accordance with his contract.

The Tribunal outlined that in order to succeed in a claim of this type a claimant must first establish that he or she is a part-time worker as defined and then identify an actual full-time worker comparator. S/he must then establish that they have been less favourably treated as regards either the terms of his or her contract or by being subjected to any other detriment, and satisfy the Tribunal that the identified less favourable treatment is on the grounds that the claimant worker is part-time.

If, and only if, all those elements are established, does the onus then shift to the employer to show that there is an objective justification for the less favourable treatment. If the employer cannot do so, the less favourable treatment complaint will be made out.

The Tribunal misdirected itself by concluding it was bound by Wippel v Peek & Cloppenburg GmbH & Co KG [2005] IRLR 211. Unlike Ms Wippel, the claimant in this case was not seeking to be paid a full-time salary irrespective of the hours he had worked and his claim was not "clearly outrageous". To determine whether the claimant and his comparator were employed under the same type of contract the EAT had to examine the mutually exclusive categories of worker set out in Reg 2(3). It held the Tribunal had erred in concluding that the type of contract that his comparator, Mr Leader, was engaged in was of a different type to that of the claimant.

“It cannot be that a zero-hours contract of itself constitutes a different type of contract for the purposes of Regulation 2, since the consequence would be that an employee on a zero-hours contract would never be able to compare him or herself to a full-time worker, when the purpose of the Regulations is to enable comparisons to be made and for unjustified less favourable treatment on grounds of part-time worker status to be prohibited. It would be self-defeating.”

Allowing the appeal, the EAT held the claimant and his comparator were employed under the same type of contract for the purposes of Regulation 2(1), (2) and (4) of the Regulations. The case was remitted back to the Tribunal to decide the remaining issues in the claim, namely, whether the part-time worker is engaged in the same, or broadly similar, work pursuant to Regulation 2(4)(a)(ii) and, if so, whether he has been subjected to unjustified less favourable treatment contrary to Regulation 5.
http://www.bailii.org/uk/cases/UKEAT/2018/0299_17_2603.html