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PostcodeLens

Data & Methodology

Last updated: July 2026

1. Data sources

Every figure on PostcodeLens comes from an official UK government dataset, published under the Open Government Licence:

  • Environment Agency: river, sea and surface water flood risk bands, and Flood Zone 2/3 designations.
  • Police.uk: recorded crime incidents, published monthly at street level.
  • HM Land Registry: Price Paid Data, the official record of registered property sales in England and Wales.
  • Office for National Statistics (ONS): postcode-to-geography lookups (outcode, sector, district, LSOA, ward).

We do not license or purchase any third-party estimates; every number traces back to one of the four sources above.

2. How area-level figures are calculated

Some postcodes have too few recorded sales or crimes to show a reliable figure without risking identifying an individual property or incident. Rather than show nothing, PostcodeLens widens the area until there's enough data, and always tells you which area a figure actually covers.

House prices: widens in this order until at least 3 transactions are found:

  • This postcode, last 12 months
  • Postcode sector, last 24 months
  • Local district, last 36 months
  • Otherwise: too few transactions to show a reliable figure

Crime: widens in this order until at least 5 incidents are found:

  • Immediate neighbourhood (LSOA), last 12 months
  • Local ward, last 24 months
  • Local district, last 12 months
  • Otherwise: too few recorded incidents to show a reliable figure

The area a figure is based on is always shown alongside it (for example "based on sales in postcode sector, last 24 months"), and we never show a widened-area figure without saying so.

3. Plain-English summaries

Where available, each postcode page includes a short AI-generated summary of the flood, crime and price data for that area. These summaries are generated from the same official figures shown elsewhere on the page; they add no new data, only a plain-English read of it. Postcodes without a generated summary yet show a template-based area overview instead.

4. Freshness & update schedule

Each source is refreshed on its own schedule, matching how often the underlying government dataset is published:

  • Flood risk: refreshed when the Environment Agency issues a new data release.
  • Crime: refreshed monthly, matching the Police.uk archive schedule.
  • House prices: refreshed monthly, matching the HM Land Registry Price Paid Data schedule.

Where we record the release behind a dataset, the date is shown next to that figure on the postcode page (for example "EA release · 2024-11" or "Police.uk release · 2026-05"), and an overall "Updated" date appears in the page's at-a-glance panel. If no date is shown for a section, we have not recorded a release date for that source yet — check the original source, linked under "Useful links" on each postcode page, for its latest publication.

5. Questions or corrections

If something looks wrong or out of date, use the "Report an issue" link on any postcode page, or see our Terms of Use for the full data accuracy disclaimer.