A headteachers' union has called on the government to back schools by stopping the return of Ofsted inspections this year, cancelling Sats and providing clarity on how GCSEs and A levels will be graded.
The NAHT school leaders' union has also raised concerns about whether it is safe for clinically vulnerable teachers to continue to come into schools as the national situation with Covid-19 worsens.
And deputy general secretary Nick Brook also renewed the union's call for schools to be reimbursed for the additional costs they are facing in meeting the government's guidelines for staying open during the pandemic.
The NAHT was responding to the announcement by prime minister Boris Johnson on Saturday evening that the country is going into a new national lockdown but that schools will be kept open.
Lockdown: Johnson says schools will remain open
The union has backed the government's decision to keep schools open but asked for "complete transparency" on the risks to children, families and school staff of keeping all pupils in school.
Mr Brook said: “We are particularly concerned that, once again, there is considerable ambiguity about whether it is safe for those who are clinically vulnerable or extremely vulnerable to continue to work in a school."
His call follows the warning from NASUWT general secretary Patrick Roach to the government that it will "need to do more in the coming days" to ensure that the most vulnerable school staff are protected.
The NAHT has also urged the Department for Education to take steps to support schools through the crisis.
Mr Brook added: "It is essential that schools are free from distractions and can focus their full efforts on the task at hand.
"The government can back schools by confirming full reimbursement of covid costs, the continued suspension of routine inspection in January, cancellation of statutory testing and clarification on arrangements for awarding GCSE, AS and A levels in summer 2021.”
Ofsted's routine inspections are currently set to return in January next year, although this date is being kept under review.
Mr Brook also asked why the DfE's guidance to schools differs from the Scottish government, which has decided that senior pupils in high-restriction areas need to wear face coverings in classrooms and that staff in all schools need to wear masks where social distancing is not possible.
He added: "We want to know from the government in England why their interpretation differs and when precisely risk factors will trigger a move to rota-working."