# Will the margin of victory for Reform UK in the 2026 Clacton by-election be above 35%

> Reform UK, ≥10% leads at 83%, runner-up 83% across 16 winner-take-all outcomes — refreshed 11 min ago.

URL: https://simplefunctions.dev/odds/clactonbymov
Updated: 2026-07-13T03:20:52.482Z
Category: politics · Topic: election-2026
Status: active
Closes: 2027-07-08

## Headline

- Leader: Reform UK, ≥10% at 83%
- Runner-up: Reform UK, ≥5% at 83%
- Outcomes: 16 (winner-take-all)
- Venue: Kalshi (16 contracts)
- 24h volume: $181

## Bound contracts (16)

| Outcome | Price | 24h | Volume | Venue | Slug |
|---|---|---|---|---|---|
| Reform UK, ≥10% | 83¢ | −4pp | $143 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p55 |
| Reform UK, ≥5% | 83¢ | −5pp | $33 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p52 |
| Reform UK, ≥15% | 78¢ | −5pp | $0 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p57 |
| Reform UK, ≥20% | 74¢ | −1pp | $0 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p60 |
| Reform UK, ≥25% | 72¢ | −4pp | $0 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p62 |
| Reform UK, ≥30% | 70¢ | +1pp | $0 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p65 |
| Reform UK, ≥35% | 68¢ | ±0 | $0 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p67 |
| Reform UK, ≥40% | 62¢ | −1pp | $0 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p70 |
| Reform UK, ≥45% | 55¢ | −4pp | $0 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p72 |
| Reform UK, ≥50% | 49¢ | −6pp | $0 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p75 |
| Reform UK, ≥55% | 45¢ | −5pp | $0 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p77 |
| Reform UK, ≥60% | 37¢ | −5pp | $0 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p80 |
| Reform UK, ≥65% | 24¢ | ±0 | $0 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p82 |
| Reform UK, ≥70% | 19¢ | −6pp | $0 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p85 |
| Reform UK, ≥75% | 16¢ | ±0 | $0 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p87 |
| Reform UK, ≥80% | 11¢ | −2pp | $5 | kalshi | /markets/will-the-margin-of-victory-for-reform-uk-in-the-20-kalshi-kxclactonbymov-clactonbyelection26sep01-ruk-p90 |

## 30-day trajectory

| Day | Reform UK, ≥10% | Reform UK, ≥5% | Reform UK, ≥15% |
|---|---|---|---|
| 2026-07-07 | 94 | 96 | 83 |
| 2026-07-08 | 93 | 94 | 88 |
| 2026-07-09 | — | 92 | — |
| 2026-07-10 | 85 | 86 | 80 |
| 2026-07-11 | 81 | 81 | 75 |

_5 days of price history captured. Each row is the daily mean of intraday 5-min captures._

## What moved the line

- 2026-07-08 · Reform UK, ≥40% +23pp 46→69¢ · kalshi
- 2026-07-08 · Reform UK, ≥35% +21pp 57→78¢ · kalshi
- 2026-07-08 · Reform UK, ≥30% +20pp 62→82¢ · kalshi
- 2026-07-08 · Reform UK, ≥25% +15pp 69→84¢ · kalshi
- 2026-07-08 · Reform UK, ≥60% +15pp 28→43¢ · kalshi

## Analysis

This contract estimates a 71% probability that Reform UK will win the 2026 Clacton by-election by more than 35 percentage points. The market reflects strong confidence in Reform's dominance in the constituency, though there is material uncertainty about whether the victory margin will exceed 35% versus a smaller but still decisive margin. Key drivers include Reform's current polling strength in Clacton, the fragmentation of opposition votes, and local candidate factors. The resolution depends on actual vote tallies when the by-election occurs; margins could narrow if opposition parties coordinate or if turnout patterns differ from expectations. The price gradient across the contract tier suggests traders see roughly 25-30 point margins as plausible, with outcomes above 35 points considered likely but not certain.

### Key factors

- Current polling and historical voting patterns in Clacton relative to Reform's national performance
- Degree of tactical voting coordination or vote-splitting among Labour, Conservative, and Liberal Democrat voters
- Local candidate quality, campaign intensity, and ground organization efforts by all competing parties
- Voter turnout rate and demographic composition of the by-election electorate compared to recent general elections
- Timing of the by-election and whether it occurs during periods of higher or lower national political salience

## Methodology

Headline is the **leader's price**, not an arithmetic mean — averaging disjoint winner-take-all outcomes is meaningless. Per-outcome prices come from the venue's last-traded mid; cross-venue values are simple means across contracts on each venue.

## How to use this data

- HTML: https://simplefunctions.dev/odds/clactonbymov
- JSON: https://simplefunctions.dev/api/public/odds?slug=clactonbymov
- Topic hub: https://simplefunctions.dev/predictions/election-2026

## License

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