Lockdown restrictions should not be lifted too early, Sir Keir Starmer has said as he warned the government "not to repeat the mistakes of last time".
The Labour leader called on the government to ensure the current lockdown is the last lockdown.
Boris Johnson has said that the earliest schools in England could start to reopen is the 8 March.
But he is coming under pressure from some of his own backbenchers to bring that date forward.
Chair of the Covid Recovery Group of Tory MPs, Mark Harper, argues that if Scotland and Wales are able to allow the return of some primary school children this month, then it should be possible to allow schools in England to re-open sooner than 8 March.
Speaking to the BBC's World at One programme, he also said he thought the government could "get rid of restrictions completely" by the end of May.
"Once you've done the top nine groups - that's 99% of deaths and over 80% of hospitalisations - that's the point at which you can get rid of restrictions completely," he said.
He expressed concern that other factors such as the rate of infection "keep being thrown into the debate" and that the "goal posts" for lifting lockdown rules were changing.
On schools, Sir Keir said he wanted classrooms "to be open as quickly as possible" but added he would prefer the prime minister to "stick to the date he's got" to make sure the country opens fully without disruption.
Concerning a wider easing of restrictions he warned the prime minister and the chancellor: "Don't repeat the mistake of last time which was to come out of lockdown too quickly, too suddenly and to lift too many restrictions because that simply led to another lockdown."
Speaking earlier this month, Health Secretary Matt Hancock set out four factors that will impact the decision to ease lockdown rules - numbers of deaths, hospitalisations, the emergence of new variants and the progress of the vaccine roll out.
Boris Johnson has also previously said that "getting things open" will also depend on "us continuing to succeed in driving the level of infection down".
Speaking at a press conference on Wednesday he said: "Though today there are some signs of hope... the level of infection is still alarmingly high."
He added that the government would be sticking to its "cautious" approach.
Currently, Scotland's lockdown will continue until at least the end of February and its youngest pupils are likely to return to school full time from 22 February
In England plans to ease lockdown will be announced around 22 February, with hopes schools will begin reopening from 8 March.
Wales's lockdown will last until at least 19 February, while in Northern Ireland the lockdown has been extended until 5 March.