Keir Starmer, the Prime Minister, has indicated a clear preference for closer ties with the European Union (EU) single market over a customs union, signaling a significant shift in the government's approach to its post-Brexit relationship with Brussels. In his clearest statements to date, Starmer told the BBC's Laura Kuenssberg that the UK should consider "even closer alignment" with the single market "if it’s in our national interest." He emphasized that "we are better looking to the single market rather than the customs union for our further alignment." This declaration tees up a new Brexit battle and suggests a deeper engagement with the EU economic bloc, while drawing a clear line against a full customs union.

Starmer elaborated on his reasoning, stating that much has changed in recent years, including the signing of new trade deals. He acknowledged his past support for a customs union with the EU but argued that "a lot of water has now gone under the bridge." He asserted that with new trade agreements secured with nations like the US and India, which he considers to be in the UK's national interest, focusing on the single market offers a more advantageous path for "further alignment." He specifically stated it "wouldn't be in our interest now to give up" these deals for a customs union. Starmer views closer economic ties as a "sovereign decision" that has already led to the best relationship with the EU "for 10 years," citing existing alignment in areas such as food, agriculture, energy, and emissions. He indicated that further alignment should be considered "on an issue-by-issue, sector-by-sector basis."

Crucially, Starmer firmly ruled out any return to EU freedom of movement rights as part of future negotiations, a system scrapped when the UK left the EU in 2019 and a key driver behind the Leave campaign. This stance aims to uphold a 2024 election manifesto pledge of "no return" to the system. However, he defended and expressed support for a youth mobility scheme, which would allow thousands of EU and UK citizens under 35 to travel, work, and gain experience in different European countries. He clarified that this is "not the return to freedom of movement," and welcomed the UK's decision to rejoin the Erasmus system for student exchanges in 2027, at an estimated cost of £570 million per year.

Despite Starmer's clear position, significant internal pressure has been mounting within the Labour party to pursue a customs union. Health Secretary Wes Streeting and Justice Secretary David Lammy have both publicly suggested that the UK could derive "enormous economic benefits" from a new customs deal. Paul Nowak, the TUC general secretary, also advocated for the "closest possible economic and political relationship with the European Union" to boost growth. Backbench pressure has been evident, with 13 Labour MPs backing a Liberal Democrat proposal to join a customs union in a Commons vote. Minouche Shafik, the prime minister’s economic adviser, is also among those who have internally suggested a return to the customs union for generating growth. However, Starmer has been more reticent, highlighting his success in signing international trade deals.

The debate has intensified, leading to warnings of a potential "civil war" within Labour if Starmer were to reverse Brexit by rejoining a customs union. Labour MP Dan Carden urged Starmer and potential leadership rivals not to pursue such an arrangement, arguing it would mean "scrapping our post-Brexit trade deals" and "giving up our hard-won national freedoms." He also pointed to figures like Manchester Mayor Andy Burnham, who hopes the UK will rejoin the EU in his lifetime, and Wes Streeting's call for a "deeper trading relationship." Labour MP Graham Stringer warned of a "rebellion of scores of Labour MPs" and "electoral suicide" for those in 'Red Wall' seats if the party breached its manifesto pledge, especially with Nigel Farage's Reform UK "breathing down their necks." Starmer himself cautioned his internal rivals against recreating the "chaos" of past Tory leadership battles, stating it "would gift Nigel Farage" and lead to a government led by Reform. He urged Labour to "turn the corner" and avoid "slogans, easy answers, quick fixes."

The Prime Minister's comments immediately drew criticism from the Conservative opposition. Shadow Foreign Secretary Dame Priti Patel accused Labour of "Brexit betrayal" and "surrendering our freedom to cut regulation and strike our own trade deals." She stated that Starmer was "unpicking and unravelling Brexit," and using it as "another excuse for him, rather than fixing the fundamental problems that he has created." Business and Trade Secretary Kemi Badenoch warned Labour against trying to boost poll ratings by "re-opening old Brexit wounds," arguing that a customs union would mean sacrificing existing trade deals and giving Brussels more leverage. She asserted that those advocating for it "do not understand what a Customs Union actually is." Conversely, Liberal Democrat foreign affairs spokesperson Layla Moran welcomed Starmer's "warm language" on EU alignment, acknowledging it as a direction her party has "long argued." However, the Liberal Democrats would prioritize a customs union over the single market, believing the UK cannot re-enter the latter without allowing full freedom of movement.

Starmer insisted that his stance is not an attempt to reverse Brexit but rather to "look forward" at the national interest, avoiding "picking over the bones of Brexit." He reiterated his commitment to his five-year mandate, having been elected in July 2024, to "change this country" and expressed confidence that by 2026, evidence of this change would be visible. He predicted the next general election would be "unlike any election we’ve seen in this country for a very, very long time," foreseeing a Labour government facing "a very rightwing proposition in Reform." Starmer characterized Reform's proposition as one of "toxic divide" and stated his belief that "to be British is to be compassionate, reasonable, live and let live, and diverse." His promotion of Nick Thomas-Symonds to full cabinet rank in November, as the minister in charge of EU negotiations, also hints at a strategic move towards strengthening ties.