London Mayor Sadiq Khan is warning that time is running out to act on the climate emergency, which will have devastating effects on the city - and could see Brent under water.

Vulnerability mapping has shown that Brent is among six London boroughs at particularly high risk of flooding and overheating, along with Islington, Hackney, Hammersmith and Fulham, Tower Hamlets and Newham.

In a speech today, ahead of key UN climate talks, Cop26, in Glasgow, Mr Khan will warn the climate emergency remains one of the biggest threats the world faces.

He will say the capital is at a crossroads, as he launches a campaign to raise awareness of the crisis and engage Londoners with changes such as the ultra low emission zone expansion to curb traffic pollution, as a new Environment Bill goes through Parliament.

Analysis suggests rising temperatures could make the Tube potentially unbearably hot for more than a month a year.

A quarter of London’s rail stations are now at high risk of flooding, and this summer parts of the city were hit by flash floods.

City Hall analysis also shows one in five schools, and nearly half of London’s hospitals, are at risk of flooding, and 200,000 homes and workplaces are at medium or high risk of surface water floods.

Furthermore, on the basis of new World Health Organisation guidelines for limits for air pollution issued yesterday (September 22), all school children in London attend schools with toxic air, officials said.

In his speech at the Barbican Centre, Mr Khan will say: “We either take bold action now or face the consequences – with catastrophic impacts on our environment, the air we breathe and the climate.

“I’m determined for London to be a world leader in tackling the twin dangers of air pollution and the climate emergency so that we can deliver a brighter future for London – one that’s greener, fairer and more prosperous for everyone.”

Mr Khan has committed to making London a zero-carbon city by 2030, and expanding the ultra low emission zone to prevent children growing up breathing toxic air.

“But I can’t do it all alone," he will say. "That’s why today I’m launching my city-wide campaign to inspire all Londoners to take action."