Boris Johnson has warned of deaths “on a grievous scale” without further action to stem the spread of coronavirus infections.
As he opened a House of Commons debate on England’s new lockdown, the prime minister urged MPs to vote in favour of a second national shutdown later on Wednesday.
Mr Johnson said he was “not prepared to take the risk with the lives of the British people” after being confronted with worsening COVID-19 data.
The prime minister added, without action now, the NHS was likely to be in “extraordinary trouble” by next month.
With Labour in support of a month-long lockdown in England, the prime minister is not at risk of seeing the Commons vote against his plans.
However, it is thought around 15 to 20 Conservative MPs could rebel and vote against the lockdown.
Mr Johnson used Wednesday’s debate to stress the lockdown would be “time-limited”, with it scheduled to end on 2 December.
However, at Prime Minister’s Questions earlier on Wednesday, the prime minister did not offer a “come what may” guarantee that the shutdown would end on that date.
Labour leader Sir Keir Starmer asked Mr Johnson: “Will the lockdown end on 2 December come what may, or will it depend on the circumstances at the time? People need to know that.”
The prime minister replied: “These measures, these autumn measures to combat the surge, will expire automatically on 2 December.
“And we will then, I hope very much, be able to get this country going again, to get businesses, to get shops open again in the run up to Christmas.
“But that depends on us all doing our bit now to make sure that we get the R down.
“I’ve no doubt that we can, and that we’ll be able to go forward from 2 December with a very, very different approach – but, of course, it will be up to the House of Commons to decide, thereafter, what to do.”
Earlier on Wednesday, Mr Johnson apologised to businesses for the “frustrations and the nightmare” of the coronavirus pandemic.
In a pre-recorded speech to the Confederation of British Industry, the prime minister said: “I want to thank you for the heroic efforts you’ve made to look after your employees, to make your premises COVID-secure, putting in Perspex screens.
“All the trouble you’ve gone to in complying with the kinds of diktats that I never believed we would have to impose which, I assure you, go completely against every free market instinct I possess.
“And, believe me, we will end these autumn measures on 2 December when they expire.”