Is burnham labour leadership succession the real shift?

Andy Burnham won the Makerfield by-election with 55% of the vote and a 20-point lead over Reform ^{[1] T The Rest Is Politics 545. Burnham Beats Reform: Britain’s Next Prime Minister? — Rory Stewart "Andy Burnham won Makerfield with 55% of the vote and a 20-point lead over Reform — in a constituency that had the sixth-highest Reform vote…" 03:38 Play} , a stunning result in a constituency that had been one of Reform's strongest performers at the prior general election. The victory triggered a rapid political realignment, with a 23% swing from Reform to Labour recorded across seats Reform had previously taken ^{[1] T The Rest Is Politics 545. Burnham Beats Reform: Britain’s Next Prime Minister? — Rory Stewart "Andy Burnham won Makerfield with 55% of the vote and a 20-point lead over Reform — in a constituency that had the sixth-highest Reform vote…" 03:38 Play} . Keir Starmer subsequently resigned as Prime Minister, having delivered Labour's third-biggest ever parliamentary majority yet departing within two years ^{[2] T The Rest Is Politics 546. Keir Starmer Resigns: What Happens Next? — Alastair Campbell "Keir Starmer won Labour's third-biggest ever parliamentary majority and resigned within two years — a brutality that says more about the st…" 05:49 Play} , paving the way for Burnham to become Britain's seventh Prime Minister since the 2016 Brexit referendum ^{[2] T The Rest Is Politics 546. Keir Starmer Resigns: What Happens Next? — Alastair Campbell "Keir Starmer won Labour's third-biggest ever parliamentary majority and resigned within two years — a brutality that says more about the st…" 05:49 Play} .