Subsidence data published earlier this year by property news site The London Property News makes for uncomfortable reading if you live in Surrey. The county sits at the intersection of England’s highest average property values and some of its most subsidence-prone clay soils, and 2025 is shaping up to be the worst year for ground movement since records began.
The numbers come from analysis of Association of British Insurers data. Subsidence payouts in the first half of 2025 alone reached £153 million, already 35% above the comparable figure for H1 2024. Based on historical patterns from comparable surge years, the full-year total for 2025 is projected to land somewhere between £275 million and £375 million, which would comfortably exceed the previous record set in 2022.
Surrey absorbs a disproportionate share of that damage. The county sits on shrink-swell clay soils that contract sharply during dry conditions, and 2025 delivered them in abundance: the February to June period was the driest on record for the South East since 2000. With an average detached home price of over £937,000, the financial exposure from a confirmed subsidence event is also higher in Surrey than almost anywhere else in England.
Why does this matter for broadband?
There is a broadband dimension to this that has gone largely unnoticed.
Openreach is targeting 25 million homes with full fibre by the end of 2026, and the South East sits squarely in the current rollout phase. Full fibre infrastructure runs underground. It relies on ducting through the same clay-rich substrates that are currently moving, cracking and settling across Surrey and the surrounding counties.
Active ground movement can crush, displace or misalign underground ducting, creating obstructions that complicate cable pulls or require remediation before an installation can proceed. In areas where subsidence is widespread, the duct network laid in previous years may no longer be in the condition surveyors originally recorded.
A spokesperson for Southern Subsidence Specialist, a subsidence repair specialist covering the southeast of England, said the timing creates a practical problem for installers that most people in the broadband industry are not yet thinking about. “Ground movement on the scale we’re seeing across the South East in 2025 doesn’t just affect buildings. It affects everything in the ground: drains, ducting, service runs. We’re seeing cases where utilities infrastructure has been disrupted by the same soil movement that’s cracking the property above it. For broadband rollout, that adds a layer of complexity to installations in affected streets that isn’t accounted for in standard survey work.”
The spokesperson added that the problem tends to surface mid-installation rather than in advance. “By the time an engineer discovers a duct is blocked or displaced, the job has already been mobilised. Rerouting above ground or pulling a new duct route is time-consuming and expensive. The underlying subsidence that caused it often hasn’t been investigated, let alone remediated.”
Copper switch-off adds urgency
With copper services due to retire in January 2027, neither Openreach nor the homeowner has the option of simply deferring. Properties that have not migrated to full fibre will lose their connection when the old network closes. In areas of active subsidence, that deadline collides with ground conditions that are not cooperating.
For Surrey homeowners in particular, the combination of record subsidence activity, high property values, and an infrastructure rollout running to a hard deadline represents a set of overlapping pressures that none of the relevant parties, Openreach, insurers, or local authorities, appears to have joined up.
The subsidence data suggests 2025 conditions are closer to a once-in-a-generation event than a routine dry year. The full fibre rollout is not pausing to wait for the ground to settle.
