This document provides an overview of the UK's past, present, and future relationship with the EU. It outlines key dates in the UK's entry and membership in the EU/EEC. It also describes some of the 40+ EU agencies the UK currently participates in. The document then discusses the red lines for the UK and EU27 in negotiating their future relationship as the UK exits the EU. The UK wants control over immigration and jurisdiction while remaining in the single market, while the EU wants to maintain the link between the single market and free movement and defend the unity of the EU.