22% — Will Reform win the next U.K. election
Kalshi 22% · 4 contracts · $2 volume · medium confidence
Updated 2026-06-26 07:47:42 UTC

Why this matters:
This probability represents an 18% chance that Reform will win the next U.K. general election. The current assessment reflects Reform's recent polling performance and organizational capacity relative to established parties like Labour and Conservative. Reform has grown from a fringe party to a notable electoral force, but still faces structural challenges in converting vote share to seat count under the U.K.'s first-past-the-post system. The probability would likely shift based on changes in national polling averages, leadership developments within Reform or competing parties, and how effectively the party can build campaign infrastructure before the election. The next major test will come through by-elections or local council results that provide clearer signals about Reform's ability to translate support into actual victories. Current uncertainty mainly stems from whether Reform's rise represents a durable realignment or a temporary protest vote.

Key factors:
- U.K. national opinion polling shows Reform typically polling between 10-20% of the vote share, but historically first-past-the-post translates this into significantly fewer parliamentary seats than Labour or Conservative parties with similar or lower percentages
- Reform has never won a general election and lacks the ground organization and candidate pipeline of established parties, which typically require years to build
- Changes in Conservative or Labour leadership, or major policy shifts, could redirect protest voters away from Reform or consolidate support around it
- By-election results and local election performance will provide concrete data on whether Reform support transfers from polls to actual ballots in contested seats
- The timing of the next general election (which can occur anytime before January 2030 under current law) affects Reform's preparation time and organizational readiness

Contracts:
- Will Labour win the next U.K. election?: Labour party — 32¢ Kalshi $2 (weight 100%)
- Will Conservative win the next U.K. election?: Conservative party — 17¢ Kalshi $0 (weight 0%)
- Will Green win the next U.K. election?: Green party — 3¢ Kalshi $0 (weight 0%)
- Will Reform win the next U.K. election?: Reform party — 35¢ Kalshi $0 (weight 0%)

---

## Methodology

SimpleFunctions aggregates live YES-side prices from Kalshi and Polymarket contracts bound to this question. For binary topics the headline is the liquidity-weighted mid-price (weight = log(1 + 24h volume) × freshness, where freshness is 1.0 if updated <24h, 0.7 if <7d, 0.4 otherwise). For multi-outcome (winner-take-all) topics the headline is the current leader's price — disjoint outcomes are never arithmetically averaged. Snapshots refresh every 5 minutes during market hours.

## SF Signal

- SF Index, regime, and 30d Brier calibration are computed separately and surfaced at https://simplefunctions.dev/admin/calibration.
- No SimpleFunctions index / regime / calibration signal is bound to this topic yet — the headline above is market-derived only.

---

*Last verified: 2026-06-26T07:20:49.338Z*

By SimpleFunctions — https://simplefunctions.dev/

Cite as: "22% per prediction markets (SimpleFunctions, June 2026)"
Canonical: https://simplefunctions.dev/answer/ukparty
Full data: https://simplefunctions.dev/api/public/query?q=Will%20Reform%20win%20the%20next%20U.K.%20election
Provider: SimpleFunctions — https://simplefunctions.dev