The EU and the UK are mutual major trading partners. With total EU UK trade in goods (exports plus imports) representing 43 % of UK total trade and 13 % of EU total trade (see Figure 3), the EU is by far the UK’s largest trading partner for goods, and the UK comes third for the EU after the United States of America (USA) and China. Moreover, the value chains involved are highly integrated: the share of EU intermediate goods used in UK production of exported goods is 48 %, and that of UK intermediate goods used in EU exports is nearly 11 %. Without an FTA, trade would take place under World Trade Organization (WTO) terms, whereby imports are subject to the schedules of tariffs and quotas determined by the importing country. An FTA without tariffs would therefore constitute a means of preserving the status quo. Nevertheless, even in the case of no duties being imposed on imports, FTAs do not remove all ‘non-tariff barriers’, which are thoroughly addressed in modern trade agreements. Two major sources of non-tariff barriers are sanitary and phytosanitary (SPS) measures and rules of origin (RoO).