Contract workers’ rights are in the spotlight in the U.K. and some EU countries as governments seek to end exploitative practices. Critics have long argued that zero-hours contracts are exploitative, because they provide no income security for contractors. The government is now stepping in, but some fear that blanket bans could restrict a company’s flexibility and growth.

Ruth Prickett graduated from Cambridge University with a BA hons in History and has specialized in business and finance journalism for the past 20 years. She was editor of Financial Management, the magazine...