All primary school children will "return to school before the summer for a month if feasible", under a government plan released today.
It also cautions that the blueprint for a return "will be kept under review".
But the news has already led to teachers' leaders calling for a rethink of the "rushed" timetable.
In the document published today, Our plan to rebuild: the UK government's Covid-19 recovery strategy, the government also reiterates plans announced by the prime minister yesterday that Reception classes and pupils in Years 1 and 6 could return to school from 1 June, adding that they would be in school in "smaller sizes".
"Secondary schools and further education colleges should also prepare to begin some face-to-face contact with Year 10 and 12 [students] who have key exams next year, in support of their continued remote home learning," it says.
But a heads' union leader has spoken of his frustration of the way the government announcement has been handled and warned that bringing Reception and Year 1 back into school after half term "is not a sensible proposal".
Geoff Barton, Association of School and College Leaders general secretary, said: “We certainly feel frustration over government communications ahead of the prime minister’s announcement on Sunday.
"There was a swirl of speculation in the media last week about schools partially reopening from 1 June, and it appears that there was some sort of government briefing that fuelled this story.
"This was disappointing, as we feel it is important that such important information should be communicated first to school and college leaders.
“In any event, it would have been a good idea to have discussed with professional associations the detail of the proposals well in advance of the prime minister’s speech, as this would have given us the opportunity to sense-check them and discuss areas that were likely to be problematic.
"We would certainly have warned that social distancing is very difficult with Reception and Year 1 children, and that the idea of bringing these groups back into school after half term is not a sensible proposal.
“We were further frustrated by the government’s failure to provide any detailed information about its plans for the reopening of schools alongside the prime minister’s speech.
"None of this is helpful in building public confidence over this important issue, and government communication will need to improve in the future. To be fair, we do not blame the Department for Education for last week’s confusion, and we have worked very constructively with them throughout the crisis.”