The legal battle over workers’ rights in the so-called “gig economy” continues to intensify, with the first of four disputes relating to the employment status of bicycle couriers scheduled to begin Tuesday.

A courier has initiated proceedings against U.K. delivery company CitySprint to demand workers’ rights, including paid vacation and rest breaks. As with the majority of gig economy workers, couriers at CitySprint are classed as self-employed, meaning they do not receive workers’ rights and protections, and also do not legally have to be paid the national minimum wage.