Video report by UK Editor Paul Brand
School children in England will return on March 8, with some in Wales and Scotland having already returned to classrooms on Monday morning.
Prime Minister Boris Johnson has revealed England's roadmap out of lockdown where he outlined a cautious approach driven by certain measures.
Scotland, Wales and Northern Ireland have all made recent announcements about their moves out of lockdown.
All four nations of the UK have said getting children back to school as soon as possible is their first priority.
When are school children returning to their desks for all four nations in the UK?
Children in England have been out of school since January 5 when the country was put back in lockdown, after some returned for a single day at the end of the Christmas break.
Primary school, secondary school and college students will be able to return to face-to-face teaching from March 8, Mr Johnson announced in the House of Commons.
Breakfast and aftershool clubs, and other children's activities, including sport, can restart "where necessary to help parents to work", Mr Johnson said.
Students on university courses requiring practical teaching, specialist facilities, or onsite assessments will be able to campuses to do so. But others will continue to learn online. The Prime Minister said the options on when other university students can return will be reviewed by the end of the Easter holidays.
Secondary school and college students will need to be tested for Covid-19 twice every week, initially at schools, and then at home.
Families and childcare bubbles will also be encouraged to get tested regularly.
Meanwhile, the government will be recommending the use of face masks in secondary schools, colleges and universities to be worn in all indoor environments, including classrooms - unless two-metre social distancing can be maintained.
Before schools were closed, secondary school children already had to wear masks in corridors. The latest advice means some children may have to wear them for practically the entire day.
Face coverings are now also recommended in early years and primary schools for staff in situations where social distancing between adults is not possible.
UK Editor Paul Brand explains how testing will work in English secondary schools
Allowing all school children to return on the same day rather than a phased return has triggered a backlash from unions representing education workers.
GMB, which represents 100,000 school workers, demanded the government introduced a phased return to classrooms where social distancing was not possible.
They also said the government should pay for all the face coverings schools need and make primary aged children wear them.
They also made a similar demand to the teaching union NASUWT which issued a fresh call for education staff to be prioritised for vaccines in the second phase of the rollout as schools reopen.
Exclusive polling for ITV News has found the vast majority of teachers do not feel safe returning to classrooms from 8th March in England.
The survey of over 7,000 teachers, conducted by the app Teacher Tapp, found 42% felt 'somewhat unsafe' fully reopening schools, while 19% felt 'very unsafe'. Headteachers felt more safe than their staff.
The youngest children in Scotland returned to school on Monday.
Children in primaries one to three, along with some senior secondary pupils who need to do practical work for qualifications, were allowed to return.
All children under school age in early learning and childcare also returned.
Senior secondary pupils will need to stick to two-metre social distancing within schools and on school buses, while Covid testing will be made available to them and teachers.Scotland has also been in lockdown since January 5.
First Minister Nicola Sturgeon announced the return of pupils to school in February but warned Scotland had very little head room to lift lockdown with current case figures and the R being just below 1.
Ms Sturgeon said it might be some time before all school-aged children returned to their classrooms.
Foundation age children - those aged between three and seven - began to return to school in Wales on Monday.
They have been away from school since mid-December when schools were closed in a bid to reign in rising infection rates.First Minister Mark Drakeford called for caution and warned that this latest easing of Wales' coronavirus lockdown restrictions was not an excuse to socialise at the school gates.If the downward trend in infection rates continues, the Welsh government's plan is for all primary school children to return to the classroom from March 15.
Not all foundation phase schoolchildren returned on Monday due to higher coronavirus infection levels in parts of the country.
In Wrexham, where cases have recently been markedly higher than other parts of Wales, schoolchildren will not return to school until Friday at the earliest.
The Stormont executive extended its lockdown until April 1 last week, but announced school pupils in year groups P1 to P3 would be allowed to return to their desks on March 8.Secondary school pupils in key exam years - year groups 12 to 14 - will return to face-to-face teaching on 22 March.But it is understood those P1-P3 pupils will return to remote learning again for a week on 22 March, the week prior to the Easter holidays, to minimise the impact on infection rates of years 12-14 returning to classes on the same date.No decisions have been taken yet on whether other year groups will return to class after the Easter holidays.