
Angela Rayner has emerged as the dominant force steering a faltering Keir Starmer, branding Home Secretary Shabana Mahmood's immigration reforms 'un-British' and forcing a swift Downing Street U-turn just this week.
The former deputy prime minister's intervention on Tuesday exposed deep rifts in Labour's top ranks, with Starmer appearing powerless to resist as his longtime strategist Morgan McSweeney has exited stage left. This power shift, unfolding in March 2026 amid dire polls ahead of May's local elections, risks tearing the party apart from within.