UK-EU customs union (duty to negotiate): Ten Minute Rule Motion

**What happened:** On 9 December 2025, the House of Commons voted on a Ten Minute Rule Motion (a backbench procedural device allowing an MP to introduce a proposed bill and make a short case for it) that would have placed a duty on the government to negotiate UK membership of the European Union customs union. The vote ended in a tie at 100 ayes and 100 noes. Under parliamentary convention, the Speaker exercises a casting vote in the event of a tie, and in this instance the Speaker voted with the ayes, meaning the motion passed. **Why it matters:** A customs union between the UK and the EU would eliminate tariffs on goods traded between them and require the UK to apply a common external tariff on imports from the rest of the world, closely aligning UK trade policy with the EU's. This would represent a significant departure from the current post-Brexit trading arrangements established under the Trade and Cooperation Agreement. In practical terms, such a change would reduce friction and costs for businesses that trade goods across UK-EU borders, but it would also constrain the UK's ability to strike its own independent trade deals with countries outside the EU. The motion, if enacted into law, would compel the government to enter negotiations, though it would not itself alter existing arrangements. **The politics:** The vote revealed a striking cross-party pattern. The Liberal Democrats provided the largest single bloc of aye votes with 67, joined by 12 Labour and 1 Labour and Co-operative MP, all 8 voting SNP members, all 4 voting Plaid Cymru members, all 3 voting Greens, both SDLP members, and 4 independents. All 89 voting Conservatives opposed the motion, as did 6 Reform UK members, 3 Labour MPs, 2 independents, and 2 further independent members. Notably, the vast majority of the Labour parliamentary party, 347 MPs, did not vote, reflecting the government's ambiguous position and apparent reluctance to be publicly associated with the measure. The outcome was determined not by a parliamentary majority but by the Speaker's casting vote, underlining how slim and contested support for the motion was.