The government’s increasingly controversial insistence that GCSE and A-level exams will go ahead next summer has been given as a key reason for keeping schools open during the next lockdown.

The NEU teaching union said yesterday that it wanted schools closed for four weeks because of increasing coronavirus rates.

But last night Boris Johnson said that keeping pupils in school was his “priority”.

Now government guidance on the new lockdown restrictions has provided detail on the rationale for schools staying open, and much of it centres on next summer’s exams.

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The guidance says: “The prime minister and education secretary have been clear that exams will go ahead next summer, as they are the fairest and most accurate way to measure a pupil’s attainment.

Coronavirus: The case for keeping schools open

“We, therefore, need to keep schools and colleges open so that children are able to keep progressing towards exams and the next stage of education or employment.”

But this week heads warned that the whole idea of holding summer exams in England was now “in jeopardy” because of growing Covid disruption.

And leaders in the North of England called for the exams to be scrapped in favour of teacher assessment to avoid another “fiasco”.

The new guidance also says schools are staying open to support pupils’ wellbeing and education and to “help working parents and guardians”.

“Senior clinicians still advise that school is the best place for children to be, and so they should continue to go to school,” it adds.

The document also appears to suggest that if education was being offered online, then leaving home for it would be breaking lockdown rules.

“You must not leave or be outside of your home except for specific purposes,” the guidance says. “These include: for childcare or education, where this is not provided online.”

But Mr Johnson was clear that schools would remain open and urged parents “to continue taking their children to school”.