Sweepscrub Services Ltd is a contract cleaning company based in London. It employs over 1,000 staff in a variety of roles, many on a part-time basis. It provides basic cleaning services to organisations throughout the region, most of the work being carried out in the evenings after office hours. For most purposes, the workforce is considered to be split into two distinct categories. The majority (850) work as cleaners. They are paid a set hourly rate and each is allocated one of three grades, based on length of service. The second category comprises the salaried staff. These are mostly employed on a full-time basis and are paid a salary for the job. These staff are engaged in a variety of roles, from supervisors who work in the field alongside the cleaners, to head office based sales staff. There are no grades, each rate being agreed on appointment and then increased as and when it is possible to do so or, more often, when someone asks for a rise.