Introduction to the special issue in “Celebrating 25 years of the EU single market”

The European Union (EU) Single Market came into existence on 1 January 1993, with the aim of bringing down barriers and simplifying existing rules so that there is the free movement of goods, capital, services, and labour—the so-called “four freedoms”—within the European Union (see Fig. 1). Over the last 25 years it has grown from 345 million citizens to about 510 million, and the number of its participating EU Member States has more than doubled: from 12 to 28 (see Table 1). In addition: Norway, Iceland, and Liechtenstein almost fully participate in the EU Single Market