Since 2006, universities in England that want to charge higher fees to their domestic undergraduates have been required to agree a plan with an access regulator appointed by the government. This article identifies the objective for the regulation as equalising opportunity, then considers its effect, drawing on policy literature, ministerial statements, legislative and regulatory texts, and national data. In doing so, it exposes how the policy objective has been implemented through legislation, regulatory guidance and university practice, and how this has yielded improving but not equalising opportunity. This is due to the limited influence of the powers available to, and guidance issued by, the regulators in a system of competing autonomous universities, which yields stratification based on the entry grades of young people and their social background. The lesson for higher education policy is the imperative for closer alignment between policy objectives, legislation to empower their implementation, approaches taken by regulators and university practice. In competitive systems within which universities have autonomy in relation to their admissions, policies to equalise opportunity require legislation and regulation that is influential enough for universities to prioritise more equitable outcomes ahead of other imperatives.