London flooding: Should the capital become a ‘sponge city’?

What constitutes sponginess is difficult to quantify.

London has an array of green spaces and there are an estimated 8.4 million trees, external in the capital, but it’s also heavily urbanised.

In 2022, British development firm Arup tried to work out London’s sponginess by using computer modelling.

The subsequent report, external compared London with seven other cities: Auckland, Mumbai, Nairobi, New York, Shanghai, Singapore and Sydney.

It found London was the second-least spongy, with a rating of 22% – only beating Sydney’s 18%.

Behind the report was Arup’s global water business lead, Mark Fletcher, who believes London should strive to become a sponge city.

Mr Fletcher told BBC London it was “just good common sense”, adding that flood management in London is “a patchwork of liability and responsibility allocation”.

He welcomes the formation of the Surface Water Strategic Group, noting that “there is progress in the right direction and all the key parties are getting around the table”.

While Arup’s results show London performing poorly, professor of urban geography at Coventry University Susanne Charlesworth said the study didn’t factor in “the age of the city, geographical location and whether there were informal settlements”.

“I’m glad they’ve called it a snapshot”, she added, highlighting how the highest-ranked cities were also the youngest.