Employers and public liability insurance are legal requirements for business and many other organisations - employers liability covers an organisation for injuries etc arising from the neglect of the employer, PL cover is the same but for members of the public. PL doesn't cover employees, people can get PL cover with their own household insurance in case (e.g. ) someone falls down a drain at your house. If you have a business, you need to approach a business insurance company or broker, they'll advise you of the levels you need.