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Next Parliament Projection

Constituency-level swing model · 2026 locals · FPTP vs PR · Coalition builder

How this projection works

Every constituency is re-projected from the GE 2024 result via a uniform proportional swing onto a national vote share you control. Each slider below shifts that target national share; the seat-level swing then plays out across all 650 constituencies.

Starting point — blends the actual GE 2024 GB vote share with the estimated 2026 local-election share (BBC PNS). At 0% the model is pure GE 2024; at 100% it's pure 2026 locals. Move the slider towards "2026" to weight the projection more heavily on the recent surge in Reform support.
Makerfield outcome — a stand-in for the political shock the Makerfield by-election would create. 🔴 Burnham holds is the neutral case: Labour retains the seat, no national mood shift, the projection is just the blended starting point. 🔵 Reform wins simulates a national bandwagon for Reform: the Reform-boost slider kicks in and adds +N pp to Reform's national share, taking 65 % of that from Labour and 35 % from "Other".
Reform boost if wins — the size of that national Reform bandwagon, in percentage points. Only takes effect when the Makerfield outcome is set to "Reform wins". Ignored under "Burnham holds".

Makerfield outcome

Starting point

GE24 2026

70% locals

Turnout adjust

calibrate locals→GE

Reform boost if wins

+3pp

Projected Parliament Composition

650 seats · majority = 326 · ideological order left → right · Seat flow GE 2024 → Projected →

Coalition Builder

Assign parties to potential coalitions · explore hung-parliament voting dynamics

Constituency Map

Hover for details · scroll or use +/− to zoom · drag to pan

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Northern Ireland

Scotland

Greater London

⚠ Scotland uses pre-2024 boundary shapes (2013 review). Constituency names are 2024. Grey = no boundary data.

Proportional Representation vs First Past The Post

D'Hondt method · same projected national vote shares · 650 seats

FPTP Constituency winner-takes-all

PR — D'Hondt Proportional to national vote share

Key Swing Seats

Projected winning margin under 5% · sorted tightest first

Computing…