Beginning from Sunday and until 30 December, London, along with England's east and southeast, will go under Tier 4 COVID-19 restrictions, equivalent to a full lockdown, as announced by UK Prime Minister Boris Johnson earlier on Saturday, despite earlier pledges not to lock down on Christmas.
"These further restrictions are a bitter blow for Londoners who were hoping to spend time with loved ones safely this Christmas, and for businesses who have already suffered so much this year. London faces its toughest Christmas since the war and the whole city will need to pull together to see us through this terrible period," Khan said in a statement.
The mayor of London accused the UK government of "continued failure to get a handle on the pandemic," saying that the "continued chaos and confusion could all have been avoided had the Government not made irresponsible promises to the public and raised expectations about the Christmas period."
"I urge Londoners to follow the new restrictions very closely, so that we can protect our NHS and prevent more tragic deaths," Khan added.
Tier 4 restrictions are the strictest in the United Kingdom's four-tier scale. They include the closure of all retail businesses, except for grocery stores and essential services. Gyms, beauty industry businesses, entertainment services, and cultural sites will all be closed as well, although church services will continue.
People will be prohibited to leave home for non-essential reasons. Those who can work remotely will be required to do so. Tier 4 areas will be closed for entry and exit for people from other areas. Outdoors gatherings will be limited to two people from two households maximum.
The UK government toughened the Christmas restrictions after detecting a new mutated strain of the coronavirus that transmits faster and accounts for over half of all recorded cases in the affected areas.