Following the EU’s acceptance of the UK’s formal request for a post-withdrawal transitional regime, a common understanding was reached that it would be desirable to base a transitional regime, in principle, on a temporary prolongation of the status quo. However, there remains tension between the political preferences of the two sides. The article examines these developments, and looks in particular at whether a “status quo” transition can be located within the legal basis of Article 50 TEU, also bearing in mind the broader constitutional context provided by the Treaties and Union principles. It investigates the exceptional nature of the powers conferred on the Union under Article 50 TEU. It concludes that there may be more difficulties in agreeing the transitional arrangements than is widely assumed.