The Prime Minister will order all hospitality venues in England to close by 10pm from this Thursday after the coronavirus alert status was raised to the second-highest level for the first time since June.
In a televised address to the nation on Tuesday evening, Mr Johnson will tell people to return to home working where it does not detrimentally affect businesses and re-state the need for mask-wearing, hand-washing and social distancing.
It comes after the Government's scientific advisers warned that coronavirus cases could increase to 50,000 per day by mid-October (see graphic below), with 200 or more deaths per day in November "if we don't change course".
Chris Whitty, the chief medical officer, suggested restrictions would be needed for another six months and said it was vital to "break unnecessary links" between households.
Mr Johnson will, for now, stop short of the two-week "circuit break" lockdown some of his advisers had favoured, but ministers are so concerned about the rising rate of infections that they have discussed scrapping the "rule of six" and banning people from different households from mixing socially.
The Prime Minister is expected to hold that option in reserve, but senior Government sources confirmed that he will encourage people to go back to working from home if they have the blessing of their employer in a fresh blow to catering and retail outlets that depend on office workers for their trade.
Cabinet ministers are split on the severity of the restrictions that should be imposed, with Rishi Sunak, the Chancellor, and Alok Sharma, the Business Secretary, understood to be among those arguing the economic case for keeping new restrictions to a minimum.
Mr Johnson also faces a backlash from many of his backbenchers, who believe any reimposition of lockdown measures will be an unnecessary danger to the economy. In addition, 32 leading scientists, academics and medics have written to the Prime Minister urging him to "step back" and "fundamentally reconsider" the Government's response to the pandemic.
The authors, who include Professors Sunetra Gupta and Carl Heneghan of Oxford University, argue that imposing blanket restrictions, which affect healthy working-age people as well as the vulnerable, will do more harm than good in the long term.
After a meeting of the Cabinet on Tuesday morning, Mr Johnson (watch him talk about a second wave of coronavirus in the video below) will chair his first meeting of the Cobra emergency committee in four months, which will be attended by the leaders of all four UK nations.
He will then make a statement in Parliament before his 8pm televised address, which will echo the way he announced the original "Stay Home" message when lockdown was first imposed.
As well as forcing pubs and restaurants to close at 10pm, Mr Johnson will legally restrict the hospitality sector to table service only, meaning buying drinks at the bar will be outlawed. Other measures that will be discussed at Cabinet include the closure of indoor concert venues and a further delay to trials of spectators returning to professional sports such as Premier League football.
Number 10 said the televised announcement would include "further ways we will confront the virus" which would be finalised at the Cabinet meeting.
On Monday night, Mr Johnson told the 1922 Committee of backbench Tory MPs that "taking action now means we may not have to take drastic action later on".
A Downing Street spokesman said on Monday night: "No one underestimates the challenges the new measures will pose to many individuals and businesses. We know this won't be easy, but we must take further action to control the resurgence in cases of the virus and protect the NHS."
Another 4,368 people tested positive for coronavirus on Monday, with another 11 deaths, and the Joint Biosecurity Committee recommended that the five-stage Covid-19 alert level be moved back up to level four from level three for the first time since June 19.
It means transmission of the virus is "high or rising exponentially" and social distancing must be in place. Under level three, there had been a "gradual relaxation of restrictions".
Making a televised address with Sir Patrick Vallance, the chief scientific adviser, on Monday (see video below), Prof Whitty said: "If we don't do enough, the virus will take off – and at the moment that is the path we're clearly on – and if we do not change course we are going to find ourselves in a very difficult problem.
"We have to break unnecessary links between households, because that is the way in which this virus is transmitted. And this means reducing social contacts whether they are at work... and also in social environments."
Prof Whitty added: "We should see this as a six-month problem that we have to deal with collectively – it's not indefinite."
His comments about breaking unnecessary links between households led to speculation that tighter social restrictions could be just days away, while Matt Hancock, the Health Secretary, hinted at curbs to households socialising.
Mr Hancock told ITV's This Morning: "Where people catch the disease tends to be in social settings, people coming around to your house, or you going out and socialising, essentially." He refused to rule out England's pubs being closed altogether.
The London Mayor Sadiq Khan, meanwhile, will on Tuesday ask the Prime Minister to impose local lockdown measures on the capital. He is calling for face coverings to be mandatory in all public spacesand a reduction in the maximum number of people at weddings and funerals, which currently stands at 30.
It will mean more than 23 million people around the country will be living under some form of local lockdown.
In Northern Ireland, the First Minister, Arlene Foster, announced a ban on the mixing of two or more households indoors.
Meanwhile, a leaked document showed that, in Scotland, proposals for a two-week "circuit break" (see video below) involved a return to full lockdown, with schools closed for an extended half term, travel restrictions of between five and 30 miles from people's homes and the closure of close contact services such as hairdressers as well as cinemas, casinos and other entertainment venues.
In the City, fears of a second lockdown wiped £51 billion off the value of the FTSE 100 share index – a 3.3 per cent drop that was its biggest fall in three months.
The White House adviser Larry Kudlow described reports that "Britain might shut down" as "a great concern" on Monday.
Pedro Sanchez, the Spanish Prime Minister, agreed to deploy the army to Madrid amid growing unrest in the city following the announcement of a strict new lockdown.