Investing in flood defences is investing in our national security – Inside track

This post is by Emma Howard Boyd CBE, visiting professor in practice, Grantham Research Institute, London School of Economics and Political Science is a former chair of the Environment Agency.

In March, the prime minister gave a speech “on the fundamental reform of the British state”. He said: “now more now than ever, national security is economic security” and “You’re not strong if one in eight young people are not in education or work… and you’re not strong if you lose control of your public finances… and you can’t build your industries. So that is the test of our times. The goal of my plan for change… national security for national renewal.”

The upcoming multi-year spending review presents an opportunity to put numbers on national security for national renewal. One crucial area to look at will be the many climate impacts that populate the National Risk Register, from wildfires to floods.

Public First has published economic and opinion research looking at the impact of flooding in its new report, From risk to resilience. I chaired the steering committee for the report which shows that over half (55 per cent) of UK adults think that communities affected by flooding will not benefit from national economic growth, due to the costs of repairs and damages. One in three (33 per cent) people polled also think the UK won’t be able to grow the economy until we deal with the immediate impacts of flooding.

Flooding threatens lives, infrastructure and the economy
In the UK, 2025 began with storms, intense rainfall and significant flooding. In Greater Manchester, the Mersey burst its banks and cars were trapped in flood water. All over the UK, major incidents were declared and, inevitably, rail services were disrupted. The M5 closed. In Lincolnshire 50 children were rescued when their school was cut off by floodwater.

Nearly two million people across the UK are exposed to flooding every year, equivalent to the combined populations of Birmingham, Sheffield and Newcastle-upon-Tyne. A third of England’s critical infrastructure – including roads, railways, energy networks and water systems – is also at risk, jeopardising national security. This is set to worsen and we must now prepare for events like last year’s flooding in Valencia that killed 224 people.

Each year of flood events causes a decade-long downward pressure on the economy worth £6.1 billion. Public First’s report shows flood events significantly impact current and future employment and output at a greater scale than the upfront cost of damage and lost output. Their modelling identified manufacturing and transportation and storage as the two sectors most affected. This is perhaps unsurprising given the type of land these sectors typically occupy and the high value equipment and capital likely kept there. However, the impact doesn’t take effect immediately, flooding starts to affect employment three years after the event, peaking at around five years.

Government must fix flood defence funding
There is no current funding commitment from the government on flood defences beyond April 2026. The chancellor allocated £2.5 billion in the Autumn budget 2024, which was topped up by £250 million following significant floods over the last few months. In 2023, the National Infrastructure Commission recommended a rolling programme of around £1.5 billion per year. Given the condition of existing flood risk management assets has degraded further since this recommendation, it is likely that more than £1.5 billion a year is required to sufficiently increase flood resilience in England.

That is value for money. Every one pound invested in flood defences prevents around eight pounds of damage. Three pounds of that is a direct saving to the government because more than a third of the damage is to publicly owned infrastructure like roads, railways, schools and hospitals.

Today, the government announced that over 1,000 flood schemes will be built or repaired to protect thousands of homes and businesses from the dangers of flooding. This is hugely welcome, but the notes to editors in the press release says “Schemes proceeding in 2026/7 and beyond will be subject to the routine RFCC consenting process and decisions at SR25 [the upcoming Spending Review].” This announcement risks giving false hope to communities and does not offer the certainty local authorities and businesses would need to make investments based on these announcements.

Another of our recommendations is to require the new National Infrastructure and Service Transformation Authority (NISTA) to track flood and wider climate resilience across all government infrastructure spending.

The National Audit Office has said: “Government cannot provide an estimate of how much it spends to manage the risks for droughts, high temperatures and heatwaves, surface water flooding and storms, because action is taken by a wide range of government departments and agencies, and no one collects this information.”

In the government’s response to the module one report of the Covid-19 Inquiry, the chancellor of the duchy of Lancaster, Pat McFadden, said: “The government’s first responsibility is to keep the public safe. That is a top priority of this government. With a long term approach to strengthening our national resilience, I shall lead a review of our national resilience against the range of risks that the UK faces.”

That review is due this year. If we measure the impact of climate risks and resilience, it will only improve the value of investment to the taxpayer. But British people already know that flooding is hitting their communities in the pocket.

National security for national renewal is an excellent statement of intent. Now, it’s time to deliver.