Local council · Swindon
South Marston
1 seat contested on Thursday 7 May 2026. 4 candidates from 4 parties.
Predicted vote share
What the model expects
Predictions are point estimates: the model's best guess, not a guarantee. The "How this prediction was made" section below lists every step that shaped this forecast.
How accurate was the model here?
Our 7 May 2026 forecast for South Marston
✗ Winner missed
, predicted Reform UK,
actual Conservative.
Major-party MAE: 24.35pp
across the parties below.
| Party | Predicted | Actual | Gap |
|---|---|---|---|
| Reform UK | 38.5% | 13.8% | +24.7pp |
| Labour | 26.6% | 5.5% | +21.2pp |
| Conservative | 30.1% | 78.8% | -48.7pp |
Positive gap = we predicted that party would win more share than they did. See the full Swindon accuracy summary or the national audit.
Candidates 2026
Parties on the ballot
- Conservative and Unionist Party
- Labour Party
- Lib Dem
- Reform UK
How this prediction was made
- Fallback (no historic match) . No prior contest results in DC bundle for this ward (likely 2026 boundary change). Synthesised prediction from council-level GE2024 aggregate + national 2024→2026 swing + county-2025 anchor where available, restricted to the parties on the 2026 ballot. Marked low confidence.
- National-share calibration . Aggregate-predicted vs national-polled mismatch corrected at strength 0.65. Multipliers — Labour ×0.82, Conservative ×1.00, Reform UK ×1.15, Liberal Democrats ×0.96, Green Party ×1.12, SNP ×1.00, Plaid Cymru ×1.00.