# Will Keir Starmer leave Prime Minister of the United Kingdom before Sep 1, 2026

> Closed. Last odds frozen 4 d ago — final outcome on the venue.

URL: https://simplefunctions.dev/odds/leavestarmer
Updated: 2026-06-23T07:20:51.227Z
Category: general
Status: historical
Closes: 2026-12-01

## Headline

- Leader: Before Jul 1, 2026 at 97%
- Runner-up: Before Aug 1, 2026 at 97%
- Outcomes: 7 (winner-take-all)
- Venue: Kalshi (7 contracts)
- 24h volume: $149K

## Bound contracts (7)

| Outcome | Price | 24h | Volume | Venue | Slug |
|---|---|---|---|---|---|
| Before Jul 1, 2026 | 97¢ | +5pp | $69K | kalshi | /markets/will-keir-starmer-leave-prime-minister-of-the-unit-kalshi-kxleavestarmer-26jul01 |
| Before Aug 1, 2026 | 97¢ | +1pp | $23K | kalshi | /markets/will-keir-starmer-leave-prime-minister-of-the-unit-kalshi-kxleavestarmer-26aug01 |
| Before Jun 23, 2026 | 96¢ | +34pp | $21K | kalshi | /markets/will-keir-starmer-leave-prime-minister-of-the-unit-kalshi-kxleavestarmer-26jun23 |
| Before Sep 1, 2026 | 96¢ | ±0 | $4K | kalshi | /markets/will-keir-starmer-leave-prime-minister-of-the-unit-kalshi-kxleavestarmer-26sep01 |
| Before Jul 23, 2026 | 95¢ | +14pp | $18K | kalshi | /markets/will-keir-starmer-leave-prime-minister-of-the-unit-kalshi-kxleavestarmer-26jul23 |
| Before Jul 24, 2026 | 94¢ | +40pp | $1K | kalshi | /markets/will-keir-starmer-leave-prime-minister-of-the-unit-kalshi-kxleavestarmer-26jul24 |
| Before Jun 27, 2026 | 92¢ | +5pp | $14K | kalshi | /markets/will-keir-starmer-leave-prime-minister-of-the-unit-kalshi-kxleavestarmer-26jun27 |

## 30-day trajectory

| Day | Before Jul 1, 2026 | Before Aug 1, 2026 | Before Jun 23, 2026 |
|---|---|---|---|
| 2026-05-28 | 17 | 39 | — |
| 2026-06-13 | 17 | 41 | — |
| 2026-06-20 | 66 | 89 | — |
| 2026-06-21 | 87 | 95 | 44 |
| 2026-06-22 | 92 | 96 | 78 |

_26 days of price history captured. Each row is the daily mean of intraday 5-min captures._

## What moved the line

- 2026-06-22 · Before Jul 24, 2026 +40pp 52→92¢ · kalshi
- 2026-06-22 · Before Jun 23, 2026 +34pp 44→78¢ · kalshi
- 2026-06-21 · Before Jun 27, 2026 +32pp 53→85¢ · kalshi
- 2026-06-21 · Before Jul 1, 2026 +21pp 66→87¢ · kalshi
- 2026-06-20 · Before Jul 1, 2026 +19pp 47→66¢ · kalshi

## Analysis

Markets are currently pricing a 61% probability that Keir Starmer will leave his position as Prime Minister before September 1, 2026—roughly four months from now. This elevated probability reflects uncertainty about the sustainability of Labour's government following its 2024 election victory. The main drivers include Labour's relatively narrow working majority in Parliament, ongoing economic pressures, and potential internal party dynamics that could force leadership changes or trigger an election. Key catalysts would include significant by-election results, major policy failures, or shifts in Labour party cohesion. The timeframe is relatively short, meaning any departure would likely stem from immediate political crisis rather than normal electoral cycles. Market pricing suggests traders view near-term stability as contested but more likely than not to hold through summer.

### Key factors

- Labour's current House of Commons majority and the number of seats required to trigger a government collapse through defections or by-election losses
- Economic indicators and public approval metrics in the UK between May and September 2026, as these typically drive confidence votes or election calls
- Internal Labour party dynamics and any major policy implementation failures that could destabilize Starmer's position
- By-election schedules and results that could shift the parliamentary arithmetic and pressure on government stability
- External shocks or crises (economic, security, or political) that could accelerate leadership change timelines

## 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/leavestarmer
- JSON: https://simplefunctions.dev/api/public/odds?slug=leavestarmer

## License

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