The U.K. left the EU customs union after the 2016 Brexit referendum, formally exiting the bloc in January 2020 under then-Prime Minister Boris Johnson. Britain remained aligned with EU trade rules during a transition period before fully leaving the customs union on Jan. 1, 2021, when the EU-U.K. Trade and Cooperation Agreement took effect.
The move restored Britain’s ability to strike independent trade deals but introduced customs checks, rules-of-origin requirements and new barriers for exporters.
Prime Minister Keir Starmer has so far ruled out rejoining the customs union, framing it as a red line while promising a broader “reset” with Brussels.
“We are getting a closer relationship with the EU on a number of fronts, including on trade and the economy,” Starmer told MPs earlier this month, adding: “We have clear red lines in relation to the single market and the customs union.”