Boris Johnson must close schools in England as part of a new national lockdown, Sir Keir Starmer has urged.
The Labour leader said it was "tragically inevitable" that pupils would have to learn from home in order to regain control over coronavirus, protect the NHS and ensure the vaccine was rolled out to millions of people.
Sir Keir said the Government must vaccinate two million people a week this month, doubling to four million a week in February.
Ahead of the Prime Minister's address to the nation on Monday night, Sir Keir said a March-style lockdown was needed, with a tougher "stay-at-home" message.
Speaking to the BBC he said: "The virus is out of control, everybody can see that, the tiered system clearly isn't working."
He said lockdown measures were needed as soon as possible to "get the virus back under control, protect the NHS which is near breaking point this January, but critically to create a space for the rollout of the vaccine, and that needs to be mission critical".
The Government's "contract" with the public would be to ensure that the tough restrictions are used to make sure the vaccine programme is completed as quickly as possible.
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He said: "We need to be the first country to complete the vaccination programme, that has to be the basic deal."
The new lockdown needed to replicate the "spirit of March", he said during a series of interviews in his Westminster office.
Mr Starmer said: "You only need to go out on the streets now to see lots of people out and about, you see trains that are half-full, we need to go back to where we were in March with very, very strong messaging about staying at home.
"I'm afraid that the closure of schools is now inevitable and therefore that needs to be part of the national plan for further restrictions."
Sir Keir suggested Scotland's example of a legally enforceable stay-at-home order should not be ruled out.
He said: "I'm not saying no to that, I'm saying what comes before that is the messaging and the decision by the Government that that is the message - stay at home. That worked in March."
He told ITV News that a wartime spirit was needed to deploy millions of doses of vaccines, including the Government working with the Opposition.
He said: "This has to be a national mission, it's one of the biggest operations we have done since the Second World War, we all need to play our part.
"I have offered my support to the Government, I do so again and I think the Government should pull everybody into this because this is the light at the end of the tunnel."
Asked whether he backed the Prime Minister's assessment that things will improve by Easter, Sir Keir said: "The problem with the Prime Minister's predictions is they are nearly always wrong.
"Back in the summer he hoped to be back to normal by November, then it was Christmas, now it is Easter.
"The one thing that I know is that if you delay taking action, you prolong the agony."
