The problem
England has 141,629 recorded flood defence assets, published free and openly with full geometry. Anyone can download them today.
Two fields in that dataset describe a national failure. Asset owner reads "Unknown" on 104,439 of them — 73.7%. And current condition is blank on 106,179 — 75.0%, covering 43,601 kilometres of defence.
Where condition is recorded, the picture is worse than it first looks: of the 35,263 assets carrying both a current and a target grade, 5,877 are below their target. But that 16.7% is computed on a quarter of the asset base. Nobody knows about the rest.
A third field compounds it. Whether an asset should be reflected in the national flood map — which underpins planning decisions and insurance pricing — reads "Not Yet Considered" on 53.4% of assets. A majority of England’s flood defences have never been assessed for whether they belong in the map that governs where houses get built.
The consequence is already documented. The National Audit Office found that for the lack of £34m in annual maintenance funding, more than 200,000 properties were at increased flood risk — while the Agency underspent its capital programme by £310m over two years.
The system
Bulwark resolves flood defence assets to the land they sit on and the organisations responsible for them — which is precisely the join the Agency cannot currently make.
The assets are geolocated lines. Land parcel boundaries are free and open. Property identifiers are free and open. Corporate ownership records exist. Nothing in that chain is paywalled at the point where Bulwark operates, and yet the ownership field sits empty on three-quarters of the estate.
It then makes the condition gap visible rather than averaged away. A national figure computed on a quarter of assets is not a national figure, and reporting it as one obscures the problem. Bulwark publishes coverage alongside every statistic.
And it surfaces the operational signals already present in the data. Asset records carry inspection histories with next-inspection dates — some of them already in the past. Overdue inspection is computable from published data and reported by nobody.
Worked examples
Two situations this system answers
A flood defence fails. The council needs to know who was responsible for maintaining it. The national record says "Unknown" — as it does for 73.7% of 141,629 assets.
Bulwark works out which piece of land each defence sits on, then who owns that land — and separates genuinely unowned defences from ones where nobody simply wrote it down.
Maintenance is prioritised using a national condition figure quoted as though it covered the estate. It is computed on the quarter of assets that have a condition grade at all.
Bulwark states how much of the country each figure actually covers, and flags defences whose next inspection date has already gone past.
Data foundation
Every dataset below is open, or its access constraint is stated
| Dataset | Publisher | What it provides |
|---|---|---|
| Spatial flood defences | Environment Agency | 141,629 assets with polyline geometry and 37 fields including current and target condition, standard of protection, owner and inspection dates. Free, open, bulk. |
| Asset management interface | Environment Agency | Per-asset inspection history, maintenance activities with planned versus actual dates, and condition over time. |
| Title boundaries | HM Land Registry via MHCLG | 8.2 million parcels under an open licence — the land the assets sit on. |
| Open property identifiers | Ordnance Survey | Free identifier and coordinate file for resolving assets to properties. |
| Corporate and overseas ownership | HM Land Registry | Who owns the land, once parcels are resolved. Free with registration, restrictive terms. |
| National flood risk assessment | Environment Agency | What the defences protect, and what happens if they fail. |
| Companies House | Companies House | Resolving named owners to organisations, and detecting distress among them. |
Capabilities
Benefits
For government
- Closes an ownership gap the Agency reports on three-quarters of its own asset register.
- Lets maintenance spending be targeted at assets whose condition is actually known, and identifies where knowledge is missing.
- Establishes who is responsible for privately owned defences, which is unanswerable today and decisive when one fails.
- Supports the flood investment programme by showing where liability is being created faster than it is being maintained.
For the public
- Communities can find out who is responsible for the defence protecting them.
- Properties relying on defences in unknown condition become visible to their owners and insurers.
- Maintenance money directed by evidence rather than by whichever assets happen to have been inspected.
Delivery
Phasing
Risks & mitigations
Some assets genuinely have no identifiable responsible party — a finding in itself, not a resolution failure. The two must be distinguished and reported separately.
Naming a private owner as responsible for a defence has legal weight. Confidence is published per match, and low-confidence attributions are never asserted.
Some assets may not warrant inspection. The product reports the gap and asks the question rather than assuming neglect.
Sources
All sources checked in August 2026. Figures carry the reference period of their source, which may differ from publication date. Where a figure could not be verified against a primary source it is not used.