4.1 The economy of the European Union (‘EU’) is larger than that of any individual country in the world, and trade within the EU amounts to approximately half of the United Kingdom’s overall imports and exports.2 Accordingly, it is desirable in an examination of the way that foreign currencies are treated under English law to pay particular attention to the euro, which has been adopted by all members of the EU apart from the United Kingdom and Denmark. As will be seen, the euro is also, for some countries that are not members of the EU, either their official or de facto currency.3