Second level

Uncertainty — United Kingdom

What the model does not yet know: seat ranges, rank probabilities and the trajectory of the projections.

Run of 2026-09-16 · 606 polls · 50,000 simulations

Seat ranges

The number on the forecast page is the centre of a distribution, not a flat prediction. Across 50,000 simulations, the 80% interval contains the outcome eight times in ten — that is the range to quote. The 95% interval is wider and more cautious; it shows how far the model concedes the race could go.

Party Projection 80% range 95% range 80% width
Reform UK 225 210–239 196–241 ±15
Labour 166 159–173 157–182 ±7
Conservative 104 91–119 87–132 ±14
Liberal Democrat 71 71–72 71–73 ±1
SNP 41 39–43 38–44 ±2
Other 13 13–14 12–14 ±1
Plaid Cymru 7 6–9 6–10 ±2
Green 7 6–7 5–7 ±1

Width — how wide the 80% range is — is the most honest single measure of a party’s uncertainty: a party whose range spans sixty seats is not projected, it is estimated.

Where each party lands

Finishing first and forming a government are two questions; finishing second is a third, and it decides the official opposition. Each bar splits a party’s simulations across those outcomes.

  • Finishes first
  • Finishes second
  • Third or lower

Convention: on a tie at the top, both parties count as first, and that simulation counts a second place for nobody.

Projection trajectory

Each point is a full model run published that day, not a poll. The line shows how OUR read of the race moved — under incoming polls, but also under model corrections.

See the numbers as a table
Run LabourConservativeLiberal DemocratSNPGreenPlaid CymruReform UKOther
2026-09-16 165.5103.871.340.76.67.3225.313.3

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