GuideThe data
Demo or real data
Demo shows made-up numbers so you can try the app; Real shows published official data, or says plainly what is missing.
Use it
Example
In Demo, Westminster preview shows the same sample figures every time. In Real the same panel names its source release, such as official-2026-06, or says the figure is unavailable.
How we calculate it
- Demo uses fixed preview areas and numbers built into the app. They are labelled "not for decisions".
- Real reads published releases from the Close Knit data service. Every figure names its source and release.
- Real covers area boundaries, crime, price per m², stock value, sold prices, schools, road, rail and aircraft noise, commute times, flood screening and planning applications.
- Forecasts are not loaded yet; Real says so.
- The Demo / Real switch shows only for developers (with
?dev=1); everyone else sees Real.
The fine print
This preview exercises the complete product contract with deterministic fixture values. It does not claim that the preview polygons or numbers are current official statistics. Production releases must publish immutable source manifests and reviewed calculations.
Demo data is deterministic fixtures for exploring the product. Real data loads from the Close Knit data service reading validated storage. When that service cannot be reached, Real mode states exactly what is unavailable instead of rendering fixtures. Real data publishes a limited set of metrics in this release; anything unpublished stays explicitly unknown.