Schools in England could be ordered to close to pupils to try to curb an "inevitable" flu pandemic.
Staff would still be expected to turn up for work, if able
The Department for Education and Skills guidance says a rapidly spreading outbreak is inevitable and could kill up to 700,000 in waves lasting months.
Public services should try to continue with available staff, it says.
But children are "highly efficient 'spreaders' of respiratory infections" - so closing schools might reduce significantly the number infected.
Work could still be set and marked - but the department has not yet come up with a way to get it to and from children at home.
"We will not know until nearer the time, when we know more about the nature of a pandemic strain of virus, and children's vulnerability to it, whether the government will advise schools and childcare settings to close to pupils for a period during a pandemic, but it is a possibility," the guidance says.
"Any such advice would affect each region only when the pandemic reached it, based on central guidance about when to close and re-open, but it is very likely that all areas would be affected at some stage."
Teachers and other staff should however come in to work as normal.
Continuing to work
A problem arises because of the duty of local authorities to provide an education service.
"Schools would remain open to staff, who could set and mark work, but getting it to and from pupils is an issue that will have to be addressed.
"We are looking into whether and how DfES can advise or assist local authorities, and will provide more guidance later this year."
Sixth forms and further education colleges would be expected to remain open.
Similarly, universities are not expected to close. Such decisions would be for individual vice-chancellors or principals, who should plan for "a range of scenarios - staying open, reducing operations and/or closing to students".