The move will trigger a by-election to replace the former prime minister in his London constituency.
GlobeSignal-AImedium certainty
Why it matters
The Labour leader will no longer represent his constituency, triggering a by-election and reshaping his role within Parliament and the party he leads.
Most affected
Starmer's Holborn and St Pancras constituents — Must elect a new MP through a by-election. Labour Party — Loses a senior member in Parliament and faces a competitive seat defense.
Likely next
Whether Labour holds Starmer's seat in the resulting by-election and who stands as the party's candidate.