This report has five principal findings on the protection of the status of Union citizenship and the related rights post-Brexit. First, the key question as to providing this protection is whether Union Citizenship continues post-Brexit, or whether Brexit extinguishes Citizenship. The report considers that continuity (“Continuity”) is the more convincing interpretation of European Union law and international law as it stands, but it also considers the alternative of creating the new status of Associate Citizenship of the Union for British nationals (“Associate Citizenship”) with related rights. Second, the report identifies two possible means of realising these models: i) legislation by the Union to clarify Continuity and ii) the Withdrawal Agreement between the EU and the UK enshrining Associate Citizenship or Continuity. Third, it is established that no revision of the Founding Treaties is needed, irrespective of the model followed. Fourth, UK citizenship law is highly flexible in line with the principle that individuals ought not to be stripped of citizenship against their will. Fifth, devolution in the UK entails that Wales may have a considerable responsibility to protect Union Citizenship rights post-Brexit.