The Part-time Workers (Prevention of Less Favourable Treatment) Regulations 2000 prohibit an employer treating part-time workers less favourably in their contractual terms and conditions than comparable full-time workers, unless different treatment can be justified on objective grounds.
Comparable workers must be on the same type of contract and carry out the same or broadly similar duties. Note that purported contractual differences may be challenged.
Note that this legislation covers both employees and workers that the employer deems not to be employees. See also Legal status of contracts.
Right to request reasons for less favourable treatment
A member of staff who thinks they are being treated less favourably has the right, under the legislation, to request a statement from the employer detailing the reasons for the less favourable treatment. The employer must respond within 21 days of the request. See Part-time Employees Letter to employer for a template letter requesting reasons for less favourable treatment.
The right to at least pro-rata payment
A part-time worker has a right to be paid wages, including holiday pay, at a rate no less than in proportion to a comparable full time worker with a comparable contract. Note that the definition of “comparable contract” has in some cases obscured this right, however employers are increasingly left with little lawful defence if staff are performing comparable duties for lower pay.
One potential aspect of any less favourable treatment of part-time workers is that this may give rise to indirect sex discrimination claims. Part-time employment tends to involve a greater proportion of women than men than full-time employment, and consequently any collective case concerning part time employees should also be looked at in relation to whether there are grounds for this type of claim.