This chapter is partly based on ideas in an article entitled ‘Autonomous and Collective Sanctions in the International Legal Order’ (2017) XXVII Italian Yearbook of International Law 3. In 2018, the UK Parliament adopted the Sanctions and Anti-Money Laundering Act, which came into force upon the UK’s withdrawal from the EU. This legislation embodies a right to impose ‘autonomous sanctions’ against other states and non-state actors on the basis that the UK will no longer be able to benefit from the EU’s collective sanctioning competence. With this piece of domestic legislation, the spotlight is again on the nature and purposes of sanctions in international law. The issue for this chapter is whether such autonomous sanctions operate in a grey area of international law, where the legality of such is unclear, in effect where practice by states might create rights. Alternatively, are a limited number of states claiming...