More than 6,000 schools face teacher strike action
More than 3,500 schools in England and Wales will be closed and some 2,600 partially closed on Thursday when two teaching unions stage strike action.
Education Secretary Michael Gove, who announced the figures, said the strike action, over pension changes, was regrettable, unnecessary and premature.
He was responding to an urgent Commons question by his shadow, Andy Burnham.
Action is being taken by members of the National Union of Teachers and the Association of Teachers and Lecturers.
They say the changes will mean they will have to work longer, pay more and get less when they retire.
Mr Gove told the Commons the strike would cause "massive inconvenience to hard-working families" and would hit working women particularly hard.
"This strike, at this time will not help our schools," he said.
He said his department had established that 3,206 schools in England would be closed and 2,206 would be partially closed on Thursday.
In total 84 academies would be shut and 128 partially closed.
Mr Gove said when the figures for England were collated on Monday, the situation with another 10,872 schools was "not at that stage known".
Further updates would be released on Wednesday and on Thursday.
In Wales, nearly 400 of approximately 1,880 schools have said they will be closed and around 440 partially closed, according to figures from local authorities.
Mr Gove said: "In order to minimise the impact of this strike on working parents I wrote last week to all local authorities, as the employers of teachers, and to all schools, emphasising their duty to keep schools open wherever possible.
"In response to requests from governors, I also laid out the flexibilities at the disposal of schools to ensure that they stayed open.
"Schools can vary staff/pupil ratios, they can depart from the national curriculum and they can draw on voluntary support from the wider community, with those who have been CRB-checked able to provide particular help.
"Nothing can replace the great teaching offered by gifted professionals, but I would far rather see schools stayed open and offered a restricted curriculum than see hard-working families have to lose a day's pay themselves or have to pay for ad hoc and expensive last-minute childcare."
Mr Burnham said: "On Thursday children should be at school, their parents at work.
"On this side we have said consistently that these strikes are a mistake."
But he said he the government could not "evade its share of the responsibility for the disruption".
About 220,000 NUT members were balloted over the pensions changes. Around nine out of 10 (92%) of those who voted, backed the strike action with a turnout of 40%.
Just over half of the ATL's members were eligible to vote - the rest are not members of the pension scheme.
Some 83% of its eligible members who voted backed the strike action - on a turn-out of 35%.
The Girls' School Association, which represents independent girls' schools, said some of its schools had ATL members who would be taking action.
But a spokeswoman said schools would remain open as usual.
"We're not aware of any schools that are closing. All schools seem to be making reasonable adjustments to keep the schools open," she said.
Civil servants are also staging strikes over pension changes.
Prime Minister David Cameron has urged them to call the action off.