It comes as modelling suggests the UK will suffer a third huge spike in deaths unless vaccines cut Covid transmission significantly.
Public Health England’s Dr Susan Hopkins warned that relaxing lockdown measures would have to be done “very slowly, very cautiously” to avoid a surge in infections.
Dr Hopkins told BBC’s Andrew Marr show on Jan 31: “Any releases that we have will have to happen very slowly, very cautiously, watching and waiting as we go, with a two-week period to watch and see the impact of that relaxation because it takes that to see what’s happening in the population.”
Mr Johnson plunged England into a third national lockdown on Jan 5 to try to curb the rapid spread of coronavirus, as the country moved to Covid Alert Level 5.
Alert Level 5, the red level, is the highest level and means there is a significant risk that the healthcare services could become overwhelmed, and strict social distancing rules are needed.
Lockdown means people will only be able to leave their homes for limited reasons, with measures expected to stay in place until March at the earliest.
The Prime Minister has stated that the pupils returning to the classroom will be the first sign of normality beginning to return. But Mr Johnson announced on Jan 27 that schools will not return following the February half-term, although he hopes that “by three weeks later – Mar 8 – it will be safe to begin the opening of schools.”
Amid concern that the return of schools could increase the ‘R’ rate of virus reproduction, officials are working on the phased approach to opening up, which would see restrictions released at least a month apart so their impact could be closely monitored.
Britain passed the grim milestone of 100,000 coronavirus deaths on Jan 26, almost a year to the day since the first recorded death.
Read more: How many Covid vaccinations have been given in my local area? Use our postcode tool to find out
When is the next lockdown review?
Lockdown reviews were initially conducted every two weeks when England was under the Tier system but this has changed since the third lockdown was introduced on Jan 5.
Promising to publish a “roadmap” on Feb 22, Mr Johnson said that would allow Britain to “begin steadily to reclaim our lives”.
When could we see the end of lockdown rules?
Although plans were set out for an initial six-week lockdown, the Prime Minister announced on Jan 27 that lockdown will continue into March.
Following this, the Prime Minister announced that the Government will provide its plan to bring the country out of lockdown on Feb 22.
The Government quietly extended lockdown laws earlier this month, which gives local councils the power to close pubs, restaurants, shops and public spaces until July 17 this year.
The Telegraph also understands that the UK could face a three-month lockdown “halfway house” after Easter, with a full reopening being delayed until those over 50 have received their second dose of the vaccine, with a phased reopening of society in the spring.
The “staggered approach” would mean that if schools open in March, shops would be unlikely to get the green light until April, while pubs and restaurants could remain closed until May.
However, The Telegraph revealed on Jan 30 that Britain may not be able to abandon social distancing rules this year unless a vaccine proves to be highly effective.
Modelling commissioned by SPI-M, a subgroup of Sage, and passed to Downing Street suggests the UK will suffer a third huge spike in deaths unless inoculation cuts transmission significantly.
The paper finds that even in a best case scenario, in which vaccines stop 85 per cent of transmission in those vaccinated, lockdown would have to be kept in place until the end of May to prevent another significant spike in deaths.
Currently, most experts think efficacy against transmission will be around 60 per cent but there is huge uncertainty.
But Mr Johnson is under pressure from Conservatives in the lockdown-sceptic Covid Recovery Group (CRG) to set out an exit strategy to ease restrictions by Mar 8.
The CRG have highlighted scientific suggestions that the most vulnerable Britons will achieve a significant level of immunity from the virus three weeks after receiving their first dose of the jab.
Since the Government has pledged to vaccinate the 14 million most vulnerable Britons by Feb 15, ministers should prepare to ease the rules three weeks later on Mar 8, the MPs said.
Following the news that the R rate had dropped below one across the UK on Jan 22, the CRG said the Government should set out milestones to end the lockdown, starting with the pressures on hospitals.
“I think restrictions can begin to be eased once a level of vaccination has been reached across vulnerable groups and pressures have eased considerably on hospitals,” the MP told the Telegraph Live Blog.
They added: “It is for the government to set out those milestones as soon as possible.”
Despite the pressure from the CRG to ease restrictions, Matt Hancock said that reaching a decision on when to lift lockdown restrictions was “difficult”.
He told a Downing Street press conference on Jan 25: “The pressure on the NHS remains huge and we’ve got to get that case rate down. Of course I understand the yearning people have to get out of this.
“The thing is that we have to look at the facts on the ground and we have to monitor those facts.
“And of course, everybody wants to have a timeline for that, but I think most people understand why it is difficult to put a timeline on it because it’s a matter of monitoring the data, and in fact this is a state-contingent and not a time-contingent question.”