As of 2010,[update] most customs unions rarely operate as a single entity and are represented in relations with other customs territories either jointly by their member state governments and the union institutions or by only the member states.
The European Union (EU) is the only trade bloc in which the union institutions have exclusive competence over the common external tariff and thus sign and ratify agreements with foreign states without direct participation of the EU member states.
The governing organs (government or other responsible administrative entity for the states and territories, secretariat or similar international organization body for the trade blocs) of the customs territories negotiate and sign trade agreements.
For example, there are border checks between the Schengen Area portions of the EU customs territory and those portions in the Common Travel Area formed by the United Kingdom, Crown Dependencies, and Ireland[citation needed].
External territories of Australia are outside its main customs zone, but the inhabited ones get preferential tariff treatment.