Latest figures suggest that four fatalities a year - and nearly three major injuries a day - are caused by violence at work.
Although the law defines who is an employee and who is a worker, it can often be hard for tribunals to decide their status in reality.
Under the 2006 Transfer of Undertakings (Protection of Employment) Regulations (TUPE), employers have to inform and consult with recognised unions about the possible implications of the transfer for affected employees.