Local council · Hampshire
Petersfield Butser
1 seat contested on Thursday 7 May 2026. 5 candidates from 5 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 Petersfield Butser
✗ Winner missed
, predicted Conservative,
actual Lib Dem.
Major-party MAE: 8.86pp
across the parties below.
| Party | Predicted | Actual | Gap |
|---|---|---|---|
| Reform UK | 34.5% | 20.3% | +14.3pp |
| Labour | 3.9% | 2.7% | +1.2pp |
| Conservative | 34.6% | 29.2% | +5.5pp |
Positive gap = we predicted that party would win more share than they did. See the full Hampshire accuracy summary or the national audit.
Recent contests
What happened last time
| Date | Type | Winner | Top share | Source |
|---|---|---|---|---|
| 2021-05-06 | Cycle | Conservative and Unionist Party | 49.6% | declaration |
| 2017-05-04 | Cycle | Conservative and Unionist Party | 53.1% | declaration |
Candidates 2026
Parties on the ballot
- Conservative and Unionist Party
- Green Party
- Labour Party
- Lib Dem
- Reform UK
How this prediction was made
- Baseline . Most recent borough result (2021-05-06)
- National Swing (STM) . Strong Transition Model: multiplicative bounded swing, dampened by 0.1 for local
- Demographics . No significant demographic adjustments for this ward
- Incumbency . No current holder data available
- New Party Entry . Reform UK estimated at 4.6% from GE/LCC proxy + swing
- Normalise . All shares scaled to sum to 100%
- Restrict to ballot . Removed 3 party/parties not standing in 2026 (SNP 0.1pp, Plaid Cymru 0.0pp, Other 0.0pp). Their share redistributed pro-rata.
- 2025 county-cycle anchor . No 2025 reference available for this council's parent area. Stage 1 uses national polling only.
- Reform realignment uplift (no-anchor councils) . No 2025 parent-county anchor available; demographic-borrow rule applied. Asian 2.2% → base target 36.0% × regional multiplier 0.85 = 30.6%. Reform 4.0% → 30.6% (lift +26.6pp). Other parties scaled pro-rata. Calibration source: Burnley 2026 ward-level Asian%↔Reform% relationship (the 2-tier district that did receive the LCC 2025 anchor).
- 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.