What is the customs union?
A customs union is a trading area in which tariffs between member countries have been abolished and a single, common tariff is applied for trade with countries outside the customs union. In the UK, ‘the customs union’ almost always refers to the EU’s customs union. This goes much further to form a more comprehensive set of arrangements, including exchanging information and collecting data. For the UK, by leaving the customs union it can negotiate trade deals independently, as it has sole control over the tariffs it charges and can use them as a negotiating concession. However, this means introducing additional customs checks on trade between the UK and the EU, making it more costly and time-consuming for businesses.
For more, read our explainer on the EU’s customs union here.