Is it unlawful to discriminate against part-time workers?

Yes, such discrimination is prohibited by the Part-time Workers (Prevention of Less Favourable Treatment) Regulations. Under these regulations, workers have the statutory right, as part-timers, to be treated the same as comparable full-time workers, that is, workers on the same type of contract with the same employer. This right is not subject to any qualifying service requirements.

A part-time worker is entitled to receive, on request, a written statement of reasons for less favourable treatment from the employer. This statement (or absence of it) may be taken into account by an employment tribunal hearing a complaint under the regulations.