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 issued a yellow warning for the East Coast and northern Scotland. Temperatures in rural England could drop to -6C, and to -10C in Scotland.
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.”
The mayor is concerned that rising bills and the cost of living are forcing more people onto the streets.
What is cold weather protocol?
Cold Weather Protocol, or Severe Weather Protocol, is an emergency response to prevent the deaths of people who sleep rough during winter.
SWEP is activated by local authorities across the country when temperatures are forecast to be lower than zero degrees for three nights, or in London for one night, according to Eden.gov.
During periods of extreme cold, housing authorities must provide facilities for rough sleepers. This is to prevent deaths as a result of weather conditions.
The Government must provide bed-and-breakfast-type accommodation for rough sleepers or other temporary acccommodation.
Rough sleepers can stay there either until the severe weather ends, or they have found other suitable accommodation, whichever is the sooner.
Rough sleepers are:
People sleeping in the open air.
People about to bed down (sitting on/in or standing next to their bedding) in the open air.
People actually bedded down (such as on the streets, in tents, doorways, parks, bus shelters, or encampments).
People in buildings or other places not designed for habitation (such as sheds, cars, stairwells, barns, car parks, derelict boats, and so on).
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.”