Video report by ITV News Correspondent Daniel Hewitt
All school children in England will return to class as soon on March 8 under lockdown lifting plans to be announced by the prime minister on Monday afternoon.
Among the changes, the rule of six is set to return on March 29 - coinciding with the start of the school holidays - to allow outdoor gatherings in time for Easter.
Outdoor gatherings of either six people - or two households of any number - will be allowed.
The first steps of lockdown lifting in England will be:
All children return to school on March 8
Picnics and coffee in public areas with one other person on March 8
Groups of six from two households allowed to meet outdoors from March 29
Outdoor sports like tennis and football can resume from March 29
Number 10 has insisted that the “stay at home” message would remain in place despite the relaxation of some restrictions.
Boris Johnson will formally announce the roadmap to MPs in the Commons at 3.30pm before addressing the nation in a press conference at 7pm.
Mr Johnson said: “I’ll be setting out a road map to bring us out of lockdown cautiously.
“Our priority has always been getting children back into school which we know is crucial for their education as well as their mental and physical wellbeing, and we will also be prioritising ways for people to reunite with loved ones safely.
“Our decisions will be made on the latest data at every step, and we will be cautious about this approach so that we do not undo the progress we have achieved so far and the sacrifices each and every one of you has made to keep yourself and others safe.
“We have therefore set four key tests which must be met before we can move through each step of the plan.”
It is understood the four tests the government are watching are currently being met which justifies the swift reopening of schools.
Vaccines deployment minister Nadhim Zahawi defended reopening all schools on 8 March.
He told ITV News the government would set out guidelines for schools to follow when they open their doors again.
"We think this is the right way to open schools, they have to be the priority, children have to get back into face-to-face physical education, that is the right thing to do," Mr Zahawi said.
"The guidance will set out exactly how we will do that safely and deliberately cautiously."
One of the key measures is how effective the vaccines are at reducing hospital admissions.
The first study of its kind in the UK was published in Scotland on Monday and found the Pfizer and Oxford/AstraZeneca jabs were shown to reduce the risk of hospital admission from the virus by up to 85% and 94% respectively.
The four tests the government is basing lockdown lifting on:
The vaccine deployment continues successfully
Evidence shows vaccines are sufficiently effective in reducing hospitalisations and deaths in those vaccinated
Infection rates do not risk a surge in hospitalisations which would put unsustainable pressure on the NHS
An increase or discovery of any variant of concern does not change the government's assessment of the risks
England's approach will be different from that of Wales and Scotland which allowed some younger children to return to school this week, but with secondary schools expected to stay closed for some time.
There is likely to be some resistance to the roadmap from people who want to keep restrictions for longer and those who want it lifting sooner.
With one in three adults in the UK have received their first dose of a coronavirus vaccine, Mr Johnson will face pressure from some Tory MPs to ease measures more quickly.
Conservative Mark Harper, leader of the Covid Recovery Group of lockdown-sceptic backbenchers, said on Sunday that all legal restrictions put in place in response to the pandemic should be lifted by the end of April.
Teaching union NASUWT, meanwhile, issued a fresh call for education staff to be prioritised for vaccines in the second phase of the rollout as schools reopen.
GMB union, which represents 100,000 school workers in the UK demanded a phased return for pupils if social distancing was not possible.
They also said the government should pay for masks in schools and pupils in primary education should wear them.
In a statement, the union said: “Let’s face it, the Government has done precious little to make schools safer between the start of lockdown and now despite having ample time.”
An announcement on the vaccine priority order for under-50s is expected to be made this week, Professor Adam Finn, a member of the Joint Committee on Vaccination and Immunisation, said on Sunday.
Over the weekend the government pledged to offer the vaccination to every adult in the country by July 31.
They also brought forward their target of vaccinating every person over 50 by two weeks to the middle of April.
Health Secretary Matt Hancock said on Sunday that there will be “weeks between the steps” so ministers can “watch carefully” the impact of each relaxation of the restrictions.
Restrictions will be eased step-by-step across the whole of England at the same time, Downing Street said, due to the current uniform spread of the virus.
Number 10 said the blueprint would seek to balance the health needs with the social and economic impacts of lockdown.
For example, outdoor activities are set to be opened earlier than indoor ones, due to the reduced risk of spreading coronavirus outside.
MPs will be given the chance to vote on the regulations enabling the road map in the coming weeks, Number 10 said.
The Shadow Health Secretary Jon Ashworth said he welcomed a cautious approach to unlocking and wants it to be driven by "data not dates".
He said: "As the lockdown begins to ease there will come a point hopefully when, through vaccination and our efforts to suppress the virus, that we don't all have to stay at home.
But for now, those of us who can stay at home will have to stay at home, but of course there are millions who can't stay at home because of the nature of their work.
"So we've got to make sure that workplaces are made Covid-secure with ventilation standards."