However, the Prime Minister added that if a series of criteria are met, which will mean the UK can start easing lockdown restrictions, schools could reopen on Monday, March 8.
Mr Johnson added he would set out plans in the week beginning February 22 for the “gradual and phased” route out of lockdown.
He said: “If we achieve our target of vaccinating everyone in the four most vulnerable groups with their first dose by February 15, and every passing day sees more progress towards that goal, then those groups (will) have developed immunity from the virus about three-weeks later, that is by March 8.
“We hope it will therefore be safe to begin the reopening of schools from Monday, March 8.
“With other economic and social restrictions being removed thereafter as and when the data permits… then or thereafter I should say.”