Multi-member district demonstrator
How district size reshapes Westminster
This page groups current Westminster constituencies into larger multi-member districts, then shows how district magnitude changes local scale, party balance, ballot pressure, and the practicality of using stable UK boundaries.
Practicality: Common working range for local multi-member districts with a usable local link
Avg candidates on ballot: ~55
Illustrative Gallagher: 1.7
Illustrative Loosemore-Hanby: 2.8
Green band marks a common working range for local multi-member districts. In UK reform terms, this is roughly where you can start combining current seats into recognisable local-authority or city-region units without losing too much local legibility. The seat split shown here is illustrative rather than a final count for any specific voting method.
Hover or click a district
Move over a grouped district to preview it, or click to keep it selected while you read its illustrative seat balance.
Illustrative seat outcome
Slice size shows illustrative seat share. Hover to preview, click to pin.
Illustrative seat outcome
Labour
Compare each slice against the same party's vote share to see where the grouped districts help or hurt it under this illustrative model.
What this demonstrator assumes
- The map starts from the canonical 2023 Open Innovations Westminster hex layout, then groups those constituencies into larger multi-member districts.
- The district lines shown here are generated by an algorithm. Their exact boundaries are not the point; they are illustrative, meant to help imagine what stable grouped districts could look like before a real boundary process aligns them with local authority, county, or combined-authority geographies.
- Current constituency vote totals are summed into each grouped district.
- Seats are shown using Sainte-Lague as a proportional benchmark. That is deliberate: it is a better UK multiparty baseline than D'Hondt if the goal is to test district magnitude rather than tilt the comparison toward larger parties.
- Different multi-member district methods can share the same district map while using different ballots and counts.
- This page isolates the district-magnitude question first, because whether a district has 3, 6, or 10 members strongly shapes both representativeness and local practicality.