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Two-fifths of London at risk of flash floods

More than 40% of London's 301,000 commercial buildings face the threat of flooding from torrential rains according to an analysis by Zurich UK.

The analysis revealed that in addition nearly half (14,780) of London’s 33,200 basements in commercial use are at risk of flooding from heavy rains. Of these, 5,692 face a ‘high’ or ‘extreme’ flood risk.

In July 2021, London homes and businesses were inundated when a month’s worth of rain fell in one day, with basements properties among the hardest hit.

The analysis has also revealed the potential impact of climate-driven weather on London’s economy.

Zurich UK chief claims office David Nichols has said that failing to prepare for more regular bouts of heavy rain could have a knock-on impact on London’s economy which accounts for a quarter of the country’s GDP.

He said, “Flash floods are one of the most serious climate threats facing the capital. Even at current levels of global warming, we saw the chaos heavy rains caused in 2021. More frequent and severe rainstorms could be hugely disruptive for Londoners, businesses and the city’s economy. Extreme weather is the new normal, and businesses need to adapt. It’s crucial that firms urgently assess the flood risks they face and put in place plans to respond and recover.”

The Centre of London research director Claire Harding said, “London faces increasing risks from heatwaves and flash flooding: and our aging infrastructure isn’t keeping up. The impacts will often be worse for Londoners living in inner city areas with high population density and little green space.”

According to the Met Office, extreme rainfall in the UK could become more frequent and severe than previously thought. New calculations suggest that 30mm of rain per hour – the threshold for flash flooding – could be two-and-a-half times more likely in London by the 2070s, compared with the 1990s.

Paving over of the capital, a lack of green spaces and increased use of basements, is piling pressure on London’s antiquated sewage system, contributing to the rise in surface water flooding.

Mr Nichols said, “It’s not too late to prepare our towns and cities for more surface water flooding, but the current the pace of change is too slow. The government needs to accelerate the retrofitting of sustainable drainage in public spaces, or rainfall will increasingly overwhelm city sewers.”

Zurich Insurance has also launched a build back better scheme to help flood-hit home and business owners improve their property resilience to future flooding. It also offers free counselling service for customers impacted by flooding.



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