蜜芽传媒

The Mayor of London, Sadiq Khan, has activated the pan-London Severe Weather Emergency Protocol to protect homeless people as temperatures are forecast to fall below 0掳C overnight.

It's the first time the protocol has been activated this winter. London's coldest night is forecast for Friday when temperatures could drop to -3掳C.

So what's behind this latest cold snap for the capital? And how long will it last?

蜜芽传媒 Radio London's Salma El-Wardany has been speaking to Met Office Meteorologist Clare Nasir.

(Image credit: Getty Images)