Live London residential forecast
What will the average London home price be in Q4 2026?
Authority combines a web-researched frontier forecast with London-specific lessons learned from 38 archived market snapshots. The result is a forecast built for developers, lenders, brokers, valuers, investors and acquisition teams.
Published 18 August 2026 · Outcome not yet resolved
London price history and forecasts
Historical points show the official quarterly London average price against the forecasts made for that quarter. The final Q4 2026 points are live forecasts; there is no official result yet. Numbered markers connect to the market events below.
Authority forecast
£549,202
The historically selected correction model applied to the live Lightning Rod HIGH forecast and the latest official London and England market data.
Lightning Rod HIGH
£540,000
Live frontier-model forecast using public web research across 23 cited sources. Authority is £9,202, or 1.7%, higher.
Historical proof
Tested on years the model was not allowed to learn from
The correction method was chosen using 2019–2022. We then opened the untouched 2023–2025 holdout once and compared both methods against the official result.
Authority error
2.13%
Average holdout MAPE
Lightning Rod error
6.05%
Average holdout MAPE
Error reduction
64.8%
Authority versus Lightning Rod
Quarterly wins
8 / 11
Untouched holdout quarters
Market timeline
Why the line moved
Forecasts are easier to use when the market story is visible beside the numbers. These dated events changed financing costs, investor demand or transaction timing during the test window.
August 2023
Bank Rate reached 5.25%
The Bank of England raised Bank Rate to 5.25%. That made mortgage affordability and refinancing much harder just as this holdout timeline begins.
Official sourceAugust 2024
The first rate cut arrived
Bank Rate fell to 5%. It was the first move in the easing direction after the 2023 peak, improving the direction of travel for mortgage costs without making borrowing cheap.
Official sourceOctober 2024
Investor purchase tax increased
The SDLT surcharge on additional dwellings rose from 3% to 5%. This directly increased acquisition costs for landlords, companies and second-home buyers in London.
Official sourceApril 2025
Temporary stamp-duty thresholds ended
The temporary residential thresholds expired on 31 March. Buyers had a reason to complete before the deadline, so the event affected transaction timing as well as the market backdrop around subsequent prices.
Official sourceSee every historical forecast number
| Target quarter | Official result | Authority | Lightning Rod LOW |
|---|---|---|---|
| 23 Q3 | £562,012 | £553,292 | £516,000 |
| 23 Q4 | £550,664 | £548,603 | £512,000 |
| 24 Q1 | £548,260 | £541,024 | £543,000 |
| 24 Q2 | £552,971 | £538,243 | £494,200 |
| 24 Q3 | £563,945 | £534,010 | £480,000 |
| 24 Q4 | £559,239 | £548,380 | £536,000 |
| 25 Q1 | £559,582 | £545,237 | £557,800 |
| 25 Q2 | £565,796 | £546,199 | £509,800 |
| 25 Q3 | £566,843 | £547,536 | £547,700 |
| 25 Q4 | £553,859 | £554,452 | £569,600 |
| 26 Q1 | £546,632 | £550,591 | £569,800 |
How Authority built the correction
1. Rebuild the past
2. Forecast each old quarter
3. Learn recurring mistakes
4. Prove it out of time
What the comparison does—and does not—prove
The historical result is a fair comparison against Lightning Rod LOW with no web research. Web access was disabled historically because an unrestricted search could reveal the later outcome.
The live comparison uses Lightning Rod HIGH with web research. The Q4 2026 result is not known yet, so we cannot claim that Authority has won the live case. We publish both numbers now and will score them against the same official resolution rule.
The backtest does show that this London-specific correction materially improved the sealed historical benchmark, including on recent data it had never seen during method selection.
Data, cost and audit trail
Public data
£0
Official UK HPI archive from HM Land Registry.
Historical model cost
$0.095
All 38 Lightning Rod LOW backtest forecasts.
Live research cost
$0.156
One Lightning Rod HIGH run with web research.
This forecast is for informational purposes only and is not investment, financial, valuation or real-estate advice. Forecasts are estimates, not guarantees.