How well are Londoners prepared for flooding?

London is susceptible to river, tidal and surface water flooding and the city has a very high concentration of high value property and infrastructure. A significant proportion of this risk is, at present, very effectively managed via the Thames Barrier, which is estimated to be protecting over £320bn of assets.

However, nearly 30% of the properties in England that are at high surface water flood risk, and around 25% at medium risk, are located in London (Environment Agency, 2024). Climate change is, and will, also increase this flood risk: rising sea levels increase the threat from storm surges flooding the Thames; and increasing rainfall intensity will increase surface water flooding and river flooding risk. In addition, the increasing prevalence of impermeable surfaces in urban environments (e.g. roads, houses, driveways, artificial lawns), currently at around 50% of the urban environment, increases the rainfall runoff that can overwhelm drainage systems (Climate Change Committee, 2025).

This increasing risk is particularly acute in London. The UK’s 3rd Climate Change Risk Assessment (CCRA) showed that “direct and indirect expected annual damages” in the London area could increase from £195m per year in the present day to £500m per year in 2080s if applying a 4°C, high population growth and reduced adaptation scenario (Sayers et al., 2020). London also has some specific vulnerabilities. The London Underground can act as a sink for excess surface water and, for 2014-2021, 66 different tube stations were flooded, with 2021 seeing 141 hours of station closures. Similarly, there is a high number of basement flats in London (approximately 56,000) that are vulnerable to flooding (Greater London Authority, 2025).

To assess how well the residents of London are prepared for current and future flood risk, we surveyed 500 residents of central London to understand their understanding of the risks and the actions that they have taken.

Our results show that over two thirds (69%) of respondents felt that they are “not very informed” (42%) or “not at all informed” (27%) regarding their flood risk. This is reflected in a poor correlation between how residents assessed their flood risk with the flood risk as calculated by England’s Environment Agency. Londoners do not feel prepared for flooding either: respondents felt that they are “not very prepared” (40%) or “not at all prepared” (41%) for flooding. 66% of respondents also reported having taken no actions to prepare for flooding.

These results point to an urgent need to communicate more widely about how residents of London should prepare for flood risk.

 

References

Climate Change Committee (2025) Progress in Preparing for Climate Change - 2025 Progress Report to Parliament. London: CCC.

Environment Agency (2024) National assessment of flood and coastal erosion risk in England 2024. Bristol, EA.

Greater London Authority (2025) Climate adaptation.

Sayers, P. B., Horritt, M., Carr, S., Kay, A., Mauz, J., Lamb, R., and Penning-Rowsell, E. (2020) Third UK Climate Change Risk Assessment (CCRA3): Future flood risk. London: CCC.