Local council · Horsham
Itchingfield, Slinfold & Warnham
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 Itchingfield, Slinfold & Warnham
✗ Winner missed
, predicted Reform UK,
actual Conservative.
Major-party MAE: 3.59pp
across the parties below.
| Party | Predicted | Actual | Gap |
|---|---|---|---|
| Reform UK | 34.3% | 27.1% | +7.2pp |
| Conservative | 27.4% | 31.7% | -4.3pp |
Positive gap = we predicted that party would win more share than they did. See the full Horsham accuracy summary or the national audit.
Recent contests
What happened last time
| Date | Type | Winner | Top share | Source |
|---|---|---|---|---|
| 2023-05-04 | Cycle | Lib Dem | 23.5% | declaration |
| 2019-05-02 | Cycle | Conservative and Unionist Party | 26.3% | declaration |
Candidates 2026
Parties on the ballot
- Conservative and Unionist Party
- Green Party
- Lib Dem
- Reform UK
How this area looks demographically
Figures are for Horsham as a whole. The same local-authority figures are used for every ward in the council, finer ward-level demographics will land in a future release.
- White British (projected May 2026): 86.9% (Census 2021: 88.2%)
- Asian heritage (projected May 2026): 2.8% (Census 2021: 2.7%)
- Average area deprivation decile: 8.1 (1 = most deprived, 10 = least)
How this prediction was made
- Baseline . Most recent borough result (2023-05-04)
- BES MRP Prior . Baseline blended with BES Wave 1-30 south_east prior (weight 15%, n=5565 regional respondents)
- National Swing (STM) . Strong Transition Model: multiplicative bounded swing, dampened by 0.1 for local
- Demographics . 2 demographic factor(s) applied
- Incumbency . No current holder data available
- New Party Entry . Reform UK estimated at 4.1% from GE/LCC proxy + swing
- Normalise . All shares scaled to sum to 100%
- Restrict to ballot . Removed 4 party/parties not standing in 2026 (Labour 11.3pp, SNP 0.0pp, Other 0.0pp, Plaid Cymru 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 2.8% → base target 36.0% × regional multiplier 0.85 = 30.6%. Reform 12.5% → 30.6% (lift +18.1pp). 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.