- Covid-19 deaths could be twice as high over the winter as they were in the first wave of the pandemic, PM Boris Johnson is expected to warn MPs later.
In a Parliamentary statement he will say there is "no alternative" as he seeks to win support for the planned four-week lockdown across England.
But Mr Johnson will explain he was "right to try every possible option" before ordering people to stay at home.
Labour has said it will back the lockdown but criticised the delay.
Mr Johnson announced at a Downing Street news conference on Saturday that strict measures would be imposed across England from Thursday, closing pubs, restaurants, gyms, non-essential shops and places of worship.
Full details of the regulations are expected to be published before MPs vote on the measure on Wednesday.
However, Housing Secretary Robert Jenrick confirmed that moving house will still be allowed during the restrictions, adding that removals firms, estate agents and tradespeople can continue to work but must follow Covid safety guidelines.
In his address to MPs, the prime minister is expected to say: "Models of our scientists suggest that unless we act now, we could see deaths over the winter that are twice as bad or more compared with the first wave.
"Faced with these latest figures, there is no alternative but to take further action at a national level."
Mr Johnson is expected to acknowledge that some MPs believe "we should have reached this decision earlier", but will defend his earlier decision to try to control the virus with "strong local action and strong local leadership".
The prime minister is due to tell MPs that the government will "seek to ease restrictions" on 2 December and return to the current three-tier system.
On Sunday, Cabinet Office minister Michael Gove said the lockdown could be extended if it took longer to bring the transmission rate of the virus down.
Mr Johnson faces a rebellion from several senior Tory MPs, including Sir Graham Brady, chairman of the 1922 Committee of backbenchers.
Mr Brady told BBC Radio 4's The Westminster Hour: "If these kinds of measures were being taken in any totalitarian country around the world, we would be denouncing it as a form of evil - and here the removal of people's fundamental liberties is going almost without comment."
What are the new restrictions?
- People will be told to stay at home except for specific reasons
- These include work which cannot be done from home, childcare or education, exercise outdoors, medical reasons, essential shopping, providing care for vulnerable people or for volunteering, and visiting members of your support bubble
- Meeting indoors or in private gardens will not be allowed, but individuals can meet one other person from another household outside in a public place
- Non-essential retail will close, but can remain open for click-and-collect delivery
- Pubs, bars, restaurants will have to close, but can still provide takeaway and delivery, excluding takeaway of alcohol
- Indoor and outdoor leisure facilities, such as gyms and swimming pools, will also close, along with entertainment venues and personal care facilities such as beauty salons
- Places of worship will close, unless they are being used for funerals, to broadcast acts of worship, individual prayer, formal childcare, or essential services such as blood donation or food banks
- Construction sites and manufacturing workplaces can remain open
- Weddings and civil partnership ceremonies will not be able to take place except in exceptional circumstances, and funerals will be limited to a maximum of 30 people
- Children will still be able to move between homes if their parents are separated
- Clinically vulnerable people will be asked to be "especially careful" but people will not be asked to resume shielding
- Overnight stays, staying in a second home, and holidays will not be allowed - including in the UK and abroad - although there are exceptions, such as work trips
- People will be told to avoid all non-essential travel by private or public transport
The "repetitive cycle" of lockdowns was damaging livelihoods, relationships and mental health, Sir Graham said, adding that it was infringing people's basic rights to freedom of association and family life.
Former cabinet minister Esther McVey said she would vote against the restrictions, adding: "The 'lockdown cure' is causing more harm than Covid.
"The world cannot be put on hold, and the government must stop pressing the pause and stop button for the whole nation on a whim, with all the disastrous effects this brings to our lives, livelihoods, health and relationships."
Former party leader Iain Duncan Smith said the lockdown decision was a "body blow" to people in England and accused the government of "giving in" to scientific advisers.
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But the prime minister will have the support of Labour Party leader Sir Keir Starmer, who said the measures were "necessary" while criticising the government for delaying them and ensuring what would be a longer, harder lockdown.
He told the BBC's Andrew Marr Show "there's a very human cost to this" after the daily reported deaths rose from 11 on the day in September when government scientific advisers recommended a short "circuit-breaker" lockdown to more than 300 in recent days.
On Sunday, the UK recorded 23,254 new confirmed cases of coronavirus and 162 deaths within 28 days of a positive test.
Elsewhere in the UK, Scotland's five-level system of Covid restrictions has now come into force.
After an extension to the furlough scheme was announced for England, First Minister Nicola Sturgeon and Scottish Tory leader Douglas Ross called for similar support to be available if Scotland needed to go into a full lockdown.
In Wales, First Minister Mark Drakeford has said the 17-day "firebreak" lockdown will end as planned on 9 November.
Schools in Northern Ireland will reopen on Monday after an extended half-term break, while other restrictions including the closure of pubs, bars and restaurants continue until 13 November.
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from Via PakapNews