London faces being moved into the highest level of coronavirus restrictions, as ministers consider plunging the capital into Tier 3.
The restrictions could have a catastrophic impact on the economy, with pubs and restaurants forced to close except for takeaway services over the busy Christmas period.
Health Secretary Matt Hancock will unveil details of new measures for London during a statement to MPs on Monday, the PA news agency understands.
But it was unclear whether they will include moving London up from Tier 2 ahead of the formal review set for Wednesday.
MPs were also told of concern for commuter areas surrounding the capital, with Essex also at risk of entering Tier 3.
Downing Street rejected London Mayor Sadiq Khan suggestions that schools could be closed early for Christmas and reopen later in January in order to control the spread of the virus, with online lessons to replace missed classes.
He also called for mass testing in schools to help identify outbreaks and for greater Government support if the capital moves into the highest tier.
The Labour mayor said imposing the toughest tier across the capital would be a “blunt instrument”, arguing that the rise in cases was not linked to hospitality venues but instead due to a significant increase in schools and colleges.
Mr Khan said ministers could use a meeting on Monday to decide London’s status rather than wait for Wednesday’s review of the allocation of tiers across England.
The mayor told Sky News: “My understanding is that Covid-O is meeting as we speak – that’s the sub-committee of the Cabinet that makes the recommendations.
“We will have to wait and see what the Government decides – it’s a Government decision, not my decision or London leaders’ decision.”
Mr Khan said “it’s possible” that a decision will be made today “because we have seen over the last few days a big increase in the virus”.
But he added: “It’s worth looking where the virus is spreading faster and it’s worth looking at the areas where we have seen the biggest increase.
“It’s worth them asking themself the question: whether a move to Tier 3 is a blunt instrument that doesn’t really address in a laser-like fashion where we are seeing the biggest problems.”
Mr Khan has written to Boris Johnson setting out his concerns.
“I am calling on the Government to urgently provide additional support to get the spread under control, save lives and livelihoods and ensure our NHS is not overwhelmed this winter,” he said.
“Increased testing is key to this, which is why I want to see regular asymptomatic testing extended to all those unable to work from home and to students and staff at London’s secondary schools, sixth-form college and FE (further education) colleges.”
Covid in London | It's apparent the numbers continue to head in the wrong direction.
This will have huge consequences on people's health, families and friends.
— Metropolitan Police (@metpoliceuk) December 14, 2020
Mr Khan said there had been “significant” coronavirus outbreaks among 10 to 19-year-olds in the capital, and that Government must consider asking schools and colleges to close early ahead of Christmas and reopen later in January.
He said all schools and colleges across London should be given “priority testing” from today and Tuesday.
Schools in Greenwich, south-east London, have already been asked to move to online learning from Tuesday.
But the Prime Minister’s official spokesman said: “We’ve consistently said that not being in school has a detrimental impact on children’s learning as well as their own personal development and mental health.
“Which is why we expect all schools and colleges to remain open until the end of term on Thursday as schools have remained open throughout the pandemic.”
In his letter to the Prime Minister, Mr Khan said the seven-day case rate had risen in 32 local authority areas in the capital compared to the previous week.
There were also 17 boroughs where the seven-day rate exceeded 200 cases per 100,000 people.
According to the latest figures, the borough of Havering has the highest coronavirus rate in London, with 1,314 new cases recorded in the seven days to December 9 – the equivalent of 506.3 cases per 100,000 people.
This is up from a rate of 321.3 in the seven days to December 2.
The figures have been calculated by PA, based on Public Health England data published on December 13 on the Government’s coronavirus dashboard.
London MPs were given a briefing on the situation in the capital by health minister Helen Whately.
One MP on the call said it was “very depressing”.
Another MP said it was the “same gloomy outlook as last week’s meeting except all the data is even worse, almost back to the levels pre-lockdown”.
The message over Christmas would be “do not mix if you don’t need to”.
Labour’s Catherine West was left with the impression Tier 3 will be necessary.
The shadow minister, who represents Hornsey and Wood Green, told PA: “I’m very disappointed that despite having the whole of the summer and the period in which London was in lockdown, the Government appears to have yet again failed to tackle the issue of isolating those with coronavirus from the majority of the population that does not have coronavirus and therefore the blunt tool of lockdown may have to be used again.
“With the case rate doubling every four days and with the incompetence of this Government in getting the isolation strategy working, I can’t see how we can keep our hospitals coping unless there is some kind of lockdown.”
A move to Tier 3 would see almost 14,000 pubs, bars, restaurants and cafes in the capital forced to close or be restricted to takeaway or delivery services.
Analysis by real estate advisers Altus Group said more than 1,500 hotels and guest houses would also have to close, with a few limited exceptions.