Why the Impending Labour Leadership Race Is Reopening the Brexit Wound

The internal truce holding the Labour Party together just shattered. After a brutal set of local election results across England, Scotland, and Wales, the quiet murmurs of discontent have exploded into an open mutiny. Keir Starmer's grip on the leadership is slipping, and his internal rivals aren't just plotting a standard leadership challenge. They're weaponizing the ultimate third rail of British politics: rejoining the European Union.

For two years, Starmer insisted that Britain would not rejoin the EU, the single market, or the customs union during his lifetime. That static position is dead. The high-profile resignation of Wes Streeting from the Cabinet, followed immediately by his declaration of intent to run for the leadership, marks a survival of the fittest era inside the party. Streeting didn't mince words at the Progress think tank conference in London, stating outright that Britain’s future lies "one day back in the European Union."

This isn't an isolated outburst. It’s a coordinated strategy designed to tap into a massive, simmering resentment among the Labour grassroots.

The Battle for the Party Soul

You can't understand the current panic without looking at the numbers. Recent polling conducted by Survation for LabourList revealed that 65% of Labour members want the party to commit to rejoining the EU at the next general election. An astonishing 87% back a return to the bloc in principle. Starmer’s cautious, slow-moving "reset" bill—designed to gently align a few regulations on food and plants—feels like a drop in the ocean to a membership that views Brexit as an unmitigated economic disaster.

Streeting knows this. By positioning himself as the pro-Europe candidate, he's making a direct play for the party's core. He openly slammed the current leadership's culture, noting that debate was viewed as division and shut down. He wants a battle of ideas.

But he isn't the only apex predator circling. Greater Manchester Mayor Andy Burnham has been cleared to run for the Makerfield by-election, aiming for a swift return to Parliament. Burnham is playing a different, equally lethal game. He isn't pitching from a London think tank; he’s presenting himself as the savior of the party's traditional heartlands, claiming Labour requires a lot of change and hasn't been good enough.

Look at how the battlefield shapes up between the three main factions:

• The Establishment (Starmer): Desperately defending a cautious, incremental approach to Europe, terrified of alienating working-class voters who backed Leave in 2016.
• The Modernizers (Streeting): Courting the metropolitan, pro-EU membership by breaking the ultimate taboo and calling for an eventual return to Brussels.
• The Regional Heavyweights (Burnham): Using massive personal popularity in the North West to pitch a populist, anti-Westminster overhaul of the party.

The Electoral Traps Waiting Outside London

It's easy to see why Streeting's pro-EU pitch works in a room full of London activists. It’s much harder to see how it survives a general election. The Makerfield by-election is a perfect case study of the danger ahead.

While Makerfield has historically been a safe Labour seat, the party's majority over Reform UK shrank to just 5,399 votes at the last general election. Since then, Nigel Farage’s party has surged in national polling while Labour's numbers have collapsed. If Burnham wins the candidacy and faces a rampant Reform UK, a campaign focused on rejoining the EU could blow up in Labour's face.

The European Union itself isn't going to make this easy either. The Survation data showed that Labour membership enthusiasm drops from 87% to 54% if rejoining means adopting the Euro. The reality is that the old UK opt-outs are gone. Any return to Brussels means accepting the single currency, joining the Schengen area, and accepting freedom of movement. It means years of exhausting negotiations.

What Happens Next

The internal machinery is already moving. Applications for the Makerfield candidacy close imminently, with the National Executive Committee set to endorse a candidate within days. If Burnham gets the nod, expect the timetable for a leadership challenge to accelerate dramatically.

If you want to track where British politics is heading over the next few months, stop watching the government's official announcements and start watching these specific pressure points:

1. Watch the Reform UK polling in northern seats: If Farage keeps gaining ground, Starmer’s allies will argue that Streeting’s pro-EU rhetoric is electoral suicide.
2. Monitor the backbench rebellions on the upcoming EU reset bill: If a significant block of Labour MPs pushes for amendments to join the customs union, Starmer’s authority is effectively gone.
3. Track Burnham’s media appearances: The moment he secures a path back to Westminster, the rhetorical attacks on the current leadership will become much sharper.

The luxury of ignoring Europe is over for the Labour Party. The civil war has begun, and the factions are playing for keeps.