How we counted

Register extract

1. Download https://files.planning.data.gov.uk/dataset/brownfield-land.csv.
2. Keep rows whose organisation-entity is one of the 45 current East of England district or unitary planning authorities, including successor mapping for Forest Heath, St Edmundsbury, Suffolk Coastal and Waveney.
3. Drop rows with a populated end-date.
4. Read the published point (WGS84). There is no polygon in the national file for most rows.
5. Sum minimum-net-dwellings and hectares, and count rows, by authority and for the region.

Benchmark: CPRE's East total is 132,338 minimum net dwellings on 2024 data. If this extract is close, coverage is good. If it is far below, missing or lagging councils need a manual backfill.

On 7 September 2026 the government withdrew the reorganisation decisions that would have merged Essex, Norfolk and Suffolk authorities. The 45 publishers still stand.

Housing need

Regional, county and some district starting points are a May 2026 compilation of the December 2024 standard method, using MHCLG Live Table 125 stock at 31 March 2025. Norfolk and Bedfordshire do not yet have a separately compiled county figure on this site. They sit inside the East of England total of 45,596 homes a year.

Thirty-year totals hold the annual starting point flat. That is a reading of the formula, not a adopted plan target.

Constraint flags

Flag	Rule in version 2	How it is derived
Permissioned	Status records a permission, prior approval, consent or a started site. Awaiting, pending, refused, withdrawn and lapsed do not count	Register field
Flood	Authority with extensive Zone 3 (Fens, Broads, Essex and Thames estuary coasts)	Authority tag
Nutrient	Point falls inside a nutrient neutrality catchment polygon	Point in polygon
Green Belt	Point falls inside a Green Belt polygon	Point in polygon
Contamination	Hazardous-substances field populated, or the name or notes record a ground-dirtying former use (gasworks, tip, refuse, sewage, tannery, foundry, smelter, chemical, filling station, scrapyard, breakers)	Register field and keyword
Industrial	Name or notes record land still in employment use (depot, dock, port, wharf, sidings, railway, freight, haulage, warehouse, abattoir, yard, industrial or business or trading estate)	Keyword
Ownership	Ownership marked mixed or unknown, or the column left blank	Register field
Housing cost	Lower-value coastal and Fenland authorities	Authority tag
BNG	Site area above 0.2 ha and below 0.5 ha	Register field
BNG-exempt	Site area of 0.2 ha or less, exempt from net gain since 6 August 2026	Register field

Contamination and industrial use were a single keyword flag in version 1, which meant the same site read as two separate arguments. They are now distinct, and no site is counted out twice.

The walk is a funnel

The map applies these flags in a fixed order, each screen running on what survived the one before, so a site is counted out once at the first reason that stops it:

1. no planning permission
2. flood
3. nutrient catchment
4. ground to clean
5. ownership
6. Green Belt
7. biodiversity net gain (0.2–0.5 ha)
8. still in employment use

Housing cost sits between steps 4 and 5 on the page as a note. It removes nothing, because the costs it describes are the costs the surrounding screens already counted.

What survives all eight is this site's workable figure. It is an illustrative screen, not a five-year housing land supply, and every site in it is still only a row on a register until somebody builds it. The stage totals are published in data/lpa-stats.json and a test rebuilds them from the raw sites on every run, so the number on the map and the number in the file cannot drift apart.

Which layers are computed

Green Belt and nutrient neutrality are point-in-polygon tests against the published MHCLG and Natural England layers, so those two colours are site-level.

Flood is not. The Environment Agency's flood-risk-zone dataset is roughly 2.7 GB against about 43 MB for Green Belt and 2 MB for the nutrient catchments, and intersecting it is out of scope for this build. Flood and housing cost remain authority tags, and contamination and industrial use are part keyword. Those four should be read as screens, not surveys.

Licence

MHCLG, Environment Agency, Natural England and the Green Belt dataset are used under the Open Government Licence v3.0. CPRE and Lichfields reports remain their copyright and are cited, not reproduced.