Fortune marks 10 years since the 2016 Brexit vote by tracing the turmoil it brought: six prime ministers since, each departure marred by scandal, defeat, or failed Brexit deals, and Keir Starmer's resignation on 22 June 2026 after a local-election drubbing. A National Bureau of Economic Research paper pegs Brexit's cost at 6% to 8% of GDP, while Office for National Statistics projections point to deaths outnumbering births from mid-2026, with growth resting on migration alone.