Emergency cold weather measures were activated by Sadiq Khan on Wednesday amid concern that plummeting temperatures posed a risk to life.
The mayor asked councils and charities to provide extra beds for people sleeping rough as forecasters predicted below-freezing conditions in the capital overnight.
The Met Office has issued a yellow warning for the East Coast and northern Scotland. Temperatures in rural England could drop to -6C, and to -10C in Scotland as Arctic air dubbed “Troll of Trondheim” smothers the UK.
In the capital, temperatures are expected to drop below freezing on Wednesday night with a cold north-westerly wind making it feel like 0C or -1C throughout Thursday - with temperatures no higher than 3C or 4C through to early next week.
Mr Khan activated the pan-London severe weather emergency protocol (SWEP) to ensure councils open additional emergency accommodation for rough sleepers.
The mayor is concerned that rising bills and the cost of living are forcing more people onto the streets.
The number sleeping rough has increased by 24 per cent in the last year. More than 3,600 people were found on the capital’s streets between June and September, according to the Chain (Combined Homelessness and Information Network) database.
Of these, more than half were sleeping rough for the first time. A total of 481 people were considered to be “living on the streets”, up 13 per cent on the same period a year earlier.
The activation of SWEP ensures that councils and homelessness charities open additional emergency accommodation for people who are sleeping rough during weather conditions that could pose a threat to life.
All boroughs have committed to the mayor’s “In for Good” principle, which means no one will be asked to leave accommodation until a support plan is in place to end their rough sleeping, even if temperatures improve.
Met Office forecaster Oli Claydon said: “Conditions are set to get colder through the week, with the worst showers across northern Scotland but also bringing much colder conditions across all the UK.”
Warmer weather is not expected until next Tuesday.
The UK Health and Security Agency has issued a cold weather alert recommending homes are warmed to at least 18C.
Dr Raquel Nunes, of Warwick Medical School, said extreme cold meant an “increased probability of respiratory and cardiovascular diseases, falls and injuries, as well as hypothermia with older people, those chronically ill, children and homeless”.
Last week Mr Khan launched his annual winter rough sleeping fundraising campaign to support young homeless Londoners.
More than 13,500 rough sleepers have been helped off the streets since 2016, according to City Hall.
Mr Khan said: “Too many people are facing a freezing winter on the streets of the capital without the safe, secure accommodation they need. Across the capital, we are doing everything we can to prevent anyone sleeping rough in these freezing conditions.
“London’s councils and charities will be working even harder this week to support some of the most vulnerable people in our city. On behalf of all Londoners I thank them for their tireless efforts.”
He urged Londoners to download the Streetlink app to report people they see sleeping rough to support services.
His Christmas campaign will raise money for four charities that work with young homeless Londoners: akt, Centrepoint, Depaul UK, and New Horizon Youth Centre.
Donations can be made at 35 TAP points, including at Waterloo, Victoria, London Bridge and Liverpool Street stations, or at https://www.taplondon.org/donate
