The architect of Labour’s landslide victory has fallen on his sword. Morgan McSweeney, the man who steered Keir Starmer to Downing Street, has resigned as Chief of Staff, a casualty of a brutal internal war that has torn the heart out of Number 10.

In the cutthroat world of Westminster, no one is indispensable. [...](asc_slot://start-slot-5)McSweeney's departure marks the end of an era for the Starmer project. He was the strategist who de-Corbynised the party and built the disciplined machine that won the 2024 election. But in government, the skills that win campaigns often fail to run countries. His resignation follows a week of chaotic briefing wars, culminating in a "botched" attempt to shore up the Prime Minister's authority that backfired spectacularly. It is a classic tale of Icarus flying too close to the sun, or perhaps, too close to Peter Mandelson.

The War Within Number 10

Insiders describe a Downing Street in paralysis. The friction between McSweeney and other senior aides had become toxic. Accusations of a "boys' club" culture and factionalism have dogged his tenure. The final straw, however, was not just internal friction but a lapse in judgment that threatened the Prime Minister himself.

• The Briefing War: McSweeney was accused of orchestrating aggressive briefings against Cabinet ministers, notably Health Secretary Wes Streeting, in a misguided attempt to assert dominance. This alienated key allies and isolated the PM.
• The Mandelson Connection: McSweeney admitted to advising Starmer to appoint Peter Mandelson as US Ambassador, a decision that has exploded in the government's face following new Epstein revelations. "I take full responsibility," he wrote, a rare admission in a town known for deflecting blame.
• The Vacuum: His exit leaves a gaping hole at the centre of power. Starmer has now lost his political brain, his communications chief, and his strategy director in quick succession.

Starmer Alone

Keir Starmer now stands increasingly alone. The "praetorian guard" that shielded him during the opposition years is gone. This is a moment of extreme danger for the Prime Minister. Without his enforcer, can he maintain discipline in a party that is already growing restless? The sharks are circling, and the opposition—and ambitious rivals within Labour—smell blood.

McSweeney's resignation is intended to be a firebreak, stopping the scandal from consuming the Prime Minister. But in politics, when the Chief of Staff goes, the spotlight inevitably shifts to the man who hired him. The buffer is gone. Starmer is now fully exposed to the elements.