BGS & Mining Remediation Authority — area-level, Great Britain

Subsidence risk in BR1 — postcode checker

Ground stability by postcode for Bromley: BGS clay shrink-swell, coalfield status, recorded landslides and the radon band around BR1.

BGS rates the area around BR1 as ground where clay shrink-swell subsidence is a possible driver of movement as climate warms.

BGS rates the area around BR1 as ground where clay shrink-swell subsidence is a possible driver of movement as climate warms. This is AREA-LEVEL British Geological Survey screening around the BR1 representative point — generalised for national overview, on ~50 m to hex-scale grids — so it describes the neighbourhood, never a single property. Subsidence risk turns on the exact plot, foundations, trees and drainage, so a specific-address check and, if flagged, a survey are essential before you offer.

The three ground-movement drivers around BR1

Clay shrink-swell (climate)

Possible → Probable

BGS GeoClimate UKCP18 rates the clay shrink-swell subsidence class around BR1 as Possible for the 2030 Average scenario, rising to Probable by 2070 as summers get hotter and drier. Clay soils shrink in dry summers and swell when wet — the UK's commonest subsidence cause.

Coal & mining

Off-coalfield

Both coal-area queries returned no match at the postcode point. This is outside the queried DHRA/DLRA coverage; it does not establish the absence of every mining hazard at the property.

BR1 is off the recorded coalfield. For the areas that are on it, see coal mining search by area.

Recorded landslides

0 nearby

The BGS National Landslide Database records no landslide events within roughly 1.4 km of the BR1 representative point.

Radon band (area context)

Class 1/6

The UKHSA/BGS Indicative Atlas puts the 1 km tile (TQ4070) around BR1 in radon class 1 of 6 — less than 1% of homes estimated at or above the radon Action Level. Radon is a separate ground gas hazard, not a cause of subsidence, but it is part of the same below-ground picture. See the BR1 radon breakdown.

Ground hazards across the BR1 area (BGS GeoSure)

The British Geological Survey rates six natural ground hazards on a 5 km hexagonal grid across Great Britain. Each line below gives the rating for the cell the BR1 representative point falls in and how far away the nearest higher-rated cell begins — the half that matters, because a Low cell can sit a few hundred metres from a Significant one. See where this cell sits on the Great Britain subsidence map.

  • Collapsible deposits

    Low

    Collapsible deposits: Low across this 65 km² area (BGS GeoSure 5 km cell); the nearest Moderate-rated cell begins about 28.2 km W.

  • Compressible ground

    Low

    Compressible ground: Low across this 65 km² area (BGS GeoSure 5 km cell); the nearest Significant-rated cell begins about 7.5 km N.

    BGS advisory: Areas of localised significant rating.

  • Landslide (slope instability)

    Moderate

    Landslide (slope instability): Moderate across this 65 km² area (BGS GeoSure 5 km cell); the nearest Significant-rated cell begins about 30.8 km SW.

    BGS advisory: Areas of localised significant rating.

  • Running sand

    Low

    Running sand: Low across this 65 km² area (BGS GeoSure 5 km cell); the nearest Moderate-rated cell begins about 2.2 km E.

  • Shrink–swell (clay subsidence)

    Significant

    Shrink–swell (clay subsidence): Significant across this 65 km² area (BGS GeoSure 5 km cell); no cell in Great Britain is rated higher for this hazard.

    BGS advisory: Areas of localised significant rating.

  • Soluble rocks (dissolution / sinkholes)

    Low

    Soluble rocks (dissolution / sinkholes): Low across this 65 km² area (BGS GeoSure 5 km cell); the nearest Significant-rated cell begins about 1.2 km S.

    BGS advisory: Areas of localised significant rating.

Mining hazard other than coal

Non-coal mining: significant likelihood across this 2.6 km² area (BGS 1 km cell) — "Underground mining is known or considered likely to have occurred in the area."; no cell in Great Britain is rated higher.

This is the BGS mining hazard dataset that EXCLUDES coal. A rating of NA means no record of NON-COAL mining (tin, lead, salt, limestone, chalk and similar) — it says nothing about coal. Coal risk is screened separately against the Mining Remediation Authority development risk areas.

BGS attaches a standing advisory note to every cell in one or more of the layers above. Because it applies to the whole of Great Britain it says nothing about BR1, so it is not shown here as a finding.

BGS notice: "Not suitable for local or site specific analysis, data is generalised for national overview uses only"

These ratings describe an area, not a building. The GeoSure cell above covers about 65 km², and the mining cell about 2.6 km² — which side of a cell edge a house falls on is arbitrary, so read the distances above as carefully as the ratings. Only a site investigation speaks to a plot.

Contains British Geological Survey materials © UKRI 2026. Contains Ordnance Survey data © Crown copyright and database right 2026. Open Government Licence v3.0. BGS GeoSure 5 km hex grid + BGS Mining hazard (not including coal) 1 km hex grid, product version Version 8.

Indicative, area-level ground-stability screening — not a site investigation. Ratings are generalised for national overview uses and do not replace a Coal Mining Risk Assessment or site-specific geotechnical survey. These bands describe the ground around the BR1 area on BGS national-overview grids — they are never a property-specific rating, and carry no distance-to-mine-shaft claim. Whether a specific home is at risk depends on its plot, foundations, trees and drainage.

Check a specific BR1 address

This page is the area picture. The £24.99 Complete report runs the clay, coal and landslide ground screen against one exact address, alongside flood, radon and the other checks — the full ground-and-risk picture before you offer.

Try or search any UK postcode

Get My Full Property Report — £24.99Ground-stability tool

Frequently asked questions

Is BR1 at risk of subsidence?

BGS rates the area around BR1 as ground where clay shrink-swell subsidence is a possible driver of movement as climate warms. These are area-level indicators from the British Geological Survey and Mining Remediation Authority — they describe the ground around BR1, not any single home. Whether a specific property is affected depends on its plot, foundations, nearby trees and drainage, so check the exact address and, if flagged, commission a survey.

What causes subsidence in this area?

The three area-level drivers we screen are: clay shrink-swell (clay soils shrinking in dry summers and swelling when wet — the commonest UK cause, worsening with climate change), past coal or other mining (ground disturbance from historic workings), and recorded landslides (slope instability). Trees, leaking drains and made ground are property-level factors a survey assesses.

Does a subsidence flag stop me getting a mortgage or insurance?

Not automatically. Area-level ground risk can raise buildings-insurance premiums or prompt a lender to ask for a survey, especially if a property has a history of movement. A tribunal- or survey-confirmed subsidence claim is more material than an area screening. Always get a buildings-insurance quote on the specific address before you commit.

How do I check subsidence risk for a specific BR1 address?

Ground stability is assessed at the property, not the outcode. The HouseCheckup Complete report runs the clay, coal and landslide screen against one exact address and pairs it with the flood, radon and other ground checks — the full picture before you offer.

Sources

Contains Mining Remediation Authority data © Mining Remediation Authority, licensed under the Open Government Licence v3.0. Contains British Geological Survey materials © UKRI 2026 (GeoClimate UKCP18 Open). Contains British Geological Survey materials © UKRI 2026, licensed under the Open Government Licence v3.0.