Flood Risk Poses Growing Threat to England’s Transport Network, OS Analysis Finds

New analysis from Ordnance Survey (OS) has revealed the extent to which England’s road and rail networks are exposed to flooding, warning that climate-related events could increasingly isolate communities and disrupt critical transport links.

Following a winter marked by storms, flood warnings and severe weather, the geospatial study identifies key “pinch points” across the country most vulnerable to river and sea flooding. The findings highlight how extreme weather could leave towns and cities partially—or in some cases completely—cut off.

Widespread exposure across road and rail

The analysis, which combines Environment Agency flood data with the OS National Geographic Database, shows that:

• 7,564km of roads—around 12% of England’s total network—are located within the highest-risk flood zones

• 3,003km of rail lines—approximately 20% of the network—are similarly exposed

These high-risk zones are defined as areas with a 1-in-1,000 annual probability of flooding, taking into account existing flood defences.

North Yorkshire has been identified as the most vulnerable local authority, with 102km of roads exposed to river flooding and 49km at risk from sea flooding.

Communities at risk of isolation

The study highlights significant risks to connectivity at a local level. More than 1,000 built-up areas have been identified where all access roads are at risk of river flooding during extreme events.

In Greater London:

• Kingston upon Thames has 73% of access roads at risk

• Sutton (51%), Waltham Forest (45%) and Hounslow (38%) also face high exposure

Greater Manchester shows even greater vulnerability:

• Salford has 66% of access roads at risk

• Old Trafford (67%) and central Manchester (45%) are also heavily exposed

Rail network vulnerabilities

Rail connectivity is similarly at risk, with 30 local authorities facing the possibility of complete rail isolation due to river flooding.

Key commuter routes, including lines serving Marlow and Henley-on-Thames, have been identified as vulnerable. Other high-risk locations include:

• Penzance (71%)

• King’s Lynn (71%)

• Walsall (67%)

• Exeter (65%)

• York (52%)

In some areas, including Kirkby-in-Furness, Collaton St Mary and parts of Great Yarmouth, all rail access routes fall within the highest-risk flood zones.

Strategic roads under pressure

Motorways and major roads are also affected, with 587km of motorway falling within high-risk flood areas.

Routes most exposed include:

• A38 – 12% at risk

• M45 – 9%

• M32 – 9%

• A58 – 8%

Disruption along these corridors could sever key links between homes, workplaces and regional economic centres.

Tidal flooding adds further risk

In addition to river flooding, 94 local authorities have been identified where all access roads are at risk from tidal or sea flooding.

In London, Newham has the highest number of access routes at risk, while Barking and Dagenham (38%), Redbridge (25%), Greenwich (20%) and Tower Hamlets also face significant exposure.

Call for data-driven resilience planning

OS said the findings underline the increasing importance of geospatial data in supporting infrastructure planning and investment decisions.

Tom Gray, Transport Market Development Lead at Ordnance Survey, said:

“Disruption from flooding on rail and road networks is increasing as climate change continues, turning what was once an occasional challenge into a persistent planning reality.

“The ability of central government, local authorities and planners to rely on comprehensive, accurate geospatial insights is essential to reduce risk, protect communities and strengthen long-term resilience.”

He added that with investment in housing, infrastructure and major construction projects continuing to grow, ensuring assets are resilient from the outset is becoming increasingly critical.

A growing infrastructure challenge

The analysis highlights the scale of the challenge facing policymakers and infrastructure providers as climate risks intensify. With key transport corridors, commuter routes and economic links

increasingly exposed, targeted investment and long-term planning will be essential to maintain network resilience and keep communities connected.