Flooding anniversary reminder of London’s vulnerability to climate emergency

One year on from the intense rainstorms of July 2021, leading London organisations have reiterated their commitment to working together to tackle the risk of flash flooding across the capital.

Over two months’ worth of rain fell on London within two hours during both of the storms on the 12th and 25th July last year. More than a thousand homes and businesses across 24 boroughs were filled with stormwater and sewage, with many Londoners made temporarily homeless and relying on emergency support.

London Councils and the Environment Agency co-chair a joint group bringing together key agencies for boosting London’s flood preparedness. This was established following initial meetings convened by the Mayor of London in the wake of last summer’s floods, with other partners on the group including the Greater London Authority, London Climate Change Partnership, London Drainage Engineers Group, London Resilience Partnership, Transport for London, and Thames Water.

The group warns that the ongoing impact of climate change, combined with the loss of permeable greenspaces, places ever greater demands on London’s drainage systems and infrastructure, which were not designed to cope with such extreme events. Together with the lack of awareness about the risk of flash flooding, this means the capital remains vulnerable to future flooding events – especially since the warming climate is expected to result in London experiencing heavy rainfall more frequently.

The joint group is supporting pan-London flood resilience measures, including improvements to London’s multi-agency incident planning and response, and better communications between agencies and with the public about flood risk.

Last month the Mayor of London – in partnership with London Councils, the Environment Agency, London Fire Brigade, and Thames Water – wrote to Londoners in 45,000 basement properties to urgently raise awareness. While the likelihood of flooding remains low for most basement properties, where it does occur the damage and risk to life can be serious.

The joint group is also working together on a long-term strategy for managing the risk to the capital.

Philip Glanville, Mayor of Hackney and Chair of London Councils’ Transport and Environment Committee, said:

“Last year’s flooding events were stark evidence of the danger posed to London by the climate emergency.

“As a huge urban built-up area relying on a significant amount of aging infrastructure, such as Victorian drainage systems, the capital is particularly vulnerable to flash flooding. Due to climate change, severe weather events such as the heavy rainfall experienced last year are only due to increase. Boroughs are therefore very concerned by the risk not only of major disruption and damaged property, but to Londoners’ lives.

“Since last summer, a lot of work has gone into improving London’s partnership arrangements and boosting resilience to flooding, as well as strengthening London local government’s work to tackle the climate crisis. While this summer’s weather has so far been hot and dry, flooding remains a continuing threat and there can be no complacency when it comes to keeping Londoners safe.”

The Mayor of London, Sadiq Khan, said:

“The climate emergency is the biggest global threat we face today. The serious flooding in London last year that was devastating for so many Londoners shows that the climate crisis is no longer a distant problem, but one that is increasingly reaching our doorsteps.

“As Mayor, I’m determined to build a better London for everyone - ensuring we are taking action now to make our city more resilient to the impacts of climate change and flooding and making London a global leader in reducing carbon emissions.”

Charlie Wood, Environment Agency London Area Director, said:

“The flooding in July 2021 led to significant surface water impacts in London to people and businesses. The impacts on people can last a long time, including to their mental health. That is why it is important to support people to prepare and know how to recover from flooding.

“Due to the changing climate these short duration intense rainfall events are likely to occur more frequently in the future. Local authorities are responsible for managing the risk of, and response to, surface water flooding, but all sources of flooding require us, local authorities, emergency responders, water companies and other partners to work together.

“We will continue to actively support our London partners to help London to adapt and become more resilient to such localised extreme rainfall events, and to identify opportunities to streamline access to funding for surface water schemes.”



Notes to editors:

1. The Flood and Water Management Act (2010) sets out the organisational responsibilities for managing flood risk. It states that local authorities are the Lead Local Flood Authorities, with statutory responsibility for leading the development of surface water management plans. Thames Water is responsible for managing sewer flooding. It should be noted that during extreme rainfall events the drainage systems managed by highways agencies, local authorities and Thames Water are overwhelmed and it is often impossible to distinguish between the flood causes. This highlights the need for partnership working to solve these risks.

2. The full membership of the Surface Water Flooding Task and Finish Group is as follows: the Chartered Institution of Water and Environmental Management, Chief Executives London Committee, the Greater London Authority, London Drainage Engineers Group, London Environmental Directors Network, London Climate Change Partnership, London Resilience Partnership, Transport for London, Thames Regional Flood and Coastal Committee, and Thames Water.


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