London could soon go into a social lockdown under a new emergency plan being prepared by ministers.
The lockdown, which could be enforced in London and most of the north of England, would see pubs, restaurants and bars ordered to close - initially for two weeks.
Households would also be banned from meeting each other in any indoor space indefinitely, The Times reports.
Schools, shops and factories would be allowed to stay open, as well as offices for staff who are not able to work from home.
This emergency plan is not a new idea: according to The Times, it was put to the cabinet's Covid-19 strategy committee before restrictions were tightened across the country on Thursday, September 24.
But fearing a backlash, six ministers, led by PM Boris Johnson, held the lockdown back.
And the day after new restrictions came into effect (Friday, September 25) London was put on the Government's official watchlist, which highlights every borough as an area of concern.
The list is put together based on a number of factors, including the rates of new cases detected in an areas, hospital admissions and specific outbreaks in communities.
Sadiq Khan would welcome a ban on household mixing, which he has been encouraging Boris Johnson to enforce in the capital.
While official data shows London is not experiencing huge increases in infections compared with the rest of the country, the Mayor does not believe this data reflects the true nature of the situation - citing other figures such as visit to GPs and calls to NHS to prove the situation is more serious than it seems.
Professor Kevin Fenton, London regional director for Public Health England, also warned of "much more widespread transmission" of Covid-19 in the capital.
He said: "As we continue our efforts, Londoners can do their bit to help by downloading the NHS Test & Trace App, adhering to government guidelines around the rule of six and remembering hands, face, space: wash your hands, wear a face covering and keep your distance."
The plans have reportedly been drawn up after local restrictions enforced in hotspots across most of the North and parts of the Midlands failed to reverse rises in infections.
And The Times quoted one Government figure, who described London's fate as "in the balance."