“(1) A part-time worker has the right not to be treated by his employer less favourably than the employer treats a comparable full-time worker - (a) as regards the terms of his contract; or (b) by being subjected to any other detriment by any act, or deliberate failure to act, of his employer. (2) The right conferred by paragraph (1) 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. (3) In determining whether a part-time worker has been treated less favourably than a comparable full-time worker the pro rata principle shall be applied unless it is inappropriate.”
“(2) In these Regulations - … “pro rata principle” means that where a comparable full-time worker receives or is entitled to receive pay or any other benefit, a part-time worker is to receive or be entitled to receive not less than the proportion of that pay or other benefit that the number of his weekly hours bears to the number of weekly hours of the comparable full-time worker; …”
“(3) In the definition of the pro rata principle and in regulations 3 and 4 “weekly hours” means the number of hours a worker is required to work under his contract of employment in a week in which he has no absences from work and does not work any overtime or, where the number of such hours varies according to a cycle, the average number of such hours.”
“ Clause 4: Principle of non-discrimination 1. In respect of employment conditions, part-time workers shall not be treated in a less favourable manner than comparable full-time workers solely because they work part time unless different treatment is justified on objective grounds. 2. Where appropriate, the principle of pro rata temporis shall apply. 3. The arrangements for the application of this clause shall be defined by the Member States and/or social partners, having regard to European legislation, national law, collective agreements and practice.”
“19. In any event, from an examination of the figures provided, the following is clear: (i) The Claimant, as a part-time worker, was required to perform 3.5% more work days proportionately than a full-time worker from 2005-2015; and (ii) The Claimant was regularly required to work more than 50% of the Duty Hours of a full-time employee, despite receiving 50% of a full-time employee’s salary. The above constitutes less favourable treatment under Regulation 5.”
“The unequal treatment at issue must therefore be justified by the existence of precise, concrete factors, characterising the employment condition concerned in its specific context and on the basis of objective and transparent criteria for examining the question whether that unequal treatment responds to a genuine need and whether it is appropriate and necessary for achieving the objective pursued: see Del Cerro Alonso[2008] ICR 145 , para 58, and Angé Serrano v European Parliament (Case C-496/08 P)[2010] ECR I-1793 , para 44.”