Labour's Sir Keir Starmer said it was "quite something" for the prime minister "to open schools one day [and] close them the next" - describing the policy on schools as "nonsense".
Schools in England will now remain closed until at least March 8 - as the UK became the only country in Europe to pass 100,000 Covid deaths, with 3,725,713 confirmed cases.
Currently, schools in Scotland are preparing to reopen next month, while schools in Wales and Northern Ireland are still scheduled to reopen after the February half term.So, how have countries on the continent fared during this very same pandemic, and could England learn from their policies?
Deputy Chief Medical Officer for England, Prof Jonathan Van-Tam, answers the many questions on Covid safety in schools:
Despite a nightly curfew in place for most of France - with limited exceptions - all schools from nursery to secondary school remain open.
For schoolchildren in France, all those aged over six must wear a face covering.
Since schools in the country reopened in September, the government has repeatedly stressed that keeping children in school was safe.
“The situation has shown that there was no particular infection in schools,” said Education Minister Jean-Michel Blanquer ahead of a return to school after Christmas.
France has had at least 3,165,449 confirmed Covid cases and 74,600 deaths.
Spain also has a nationwide curfew in place and again schools remain open.
Again, it is compulsory for all children aged six or over to wear a face covering on public transport and indoor spaces.
Covid measures have been introduced in schools - with class sizes reduced and some secondary school students alternating between going into school and learning remotely.
Spain has at least 2,670,102 reported Covid cases and 57,291 deaths.
Many schools in Italy are reopening at half capacity - with specific classes going in on alternating days to limit mixing - though there is a regional approach to reopening.
Face coverings are compulsory for children over six and students have their temperatures checked at the start of the day.
The country has at least 2,501,147 confirmed cases and 86,899 deaths.
Sweden's Public Health Agency says: "There is no scientific evidence indicating that such an intervention [closing schools] would have any significant impact on the pandemic, nor has any major transmission of Covid-19 in schools been reported."
Schools in the country are not covered by the wider ban on public gatherings with more than eight people.
Sweden has reported at least 560,472 Covid cases and 11,425 deaths.
Secondary schools are currently teaching remotely in Greece, though nurseries and primary schools reopened in January despite a strict nationwide lockdown.
Teachers and students have been advised to sign up for a free coronavirus test before returning to class
In Greece, at least 154,083 cases have been reported and 5,724 deaths.
Germany is perhaps most in line with England, having extended its Covid lockdown until February 14 - with schools shut across the country.
Students are instead learning remotely and there are some special arrangements for young people due to sit their final year exams.
Announcing the measures, the German government said there was credible evidence that the mutated form of the virus spreads more quickly among children and adolescents.
"We must take such evidence very seriously indeed," Chancellor Angela Merkel said.
Cases in Germany stand at around 2,181,720 with reported deaths at 55,038.