The roles of professional associations have been variously defined: "A group, of people in a learned occupation who are entrusted with maintaining control or oversight of the legitimate practice of the occupation;" also a body acting "to safeguard the public interest;" organizations which "represent the interest of the professional practitioners," and so "act to maintain their own privileged and powerful position as a controlling body." In the UK, the Science Council defines a professional body as "an organisation with individual members practicing a profession or occupation in which the organisation maintains an oversight of the knowledge, skills, conduct and practice of that profession or occupation". The Quality Assurance Agency distinguishes between statutory bodies and regulators that "have powers mandated by Parliament to regulate a profession or group of professions and protect the use of professional titles" and professional bodies that "are independent membership organisations that oversee the activities of a particular profession and represent the interests of members" and which "may offer registration or certification of unregulated occupations on a voluntary basis."