Many organisations now insist that their Contractors carry their own professional indemnity insurance. They will usually require evidence of insurance cover in the form of the policy document or a certificate.
For regulated professions such as Accountants, Chartered Surveyors, Architects, Solicitors, Financial Advisers, PI is usually stipulated as a requirement of their professional bodies.
Because of the rise in litigation cases involving professional services, many businesses now also choose to take out professional indemnity to protect themselves in case they are sued for mistakes they make.