The number of pupils attending school could drop following the Government’s “rushed” lockdown announcement, a headteachers’ union has warned.

Boris Johnson has said schools, colleges and nurseries in England will stay open during the second lockdown.

But Paul Whiteman, general secretary of NAHT school leaders’ union, said the announcement on Saturday evening will not have inspired public confidence, and many families could be left wondering what is safe.

The latest Government figures show that school attendance dropped from 89% to 86% in the week ahead of the October half-term break.

Around 82% of secondary school pupils were in class on October 22, while attendance in primary schools dropped to 90%.

Mr Whiteman has said it is likely that more pupils will stay at home as term restarts – and he has called on the Government to remove parental fines for non-attendance in light of the national restrictions.

He said: “The rushed, last-minute nature of the lockdown announcement on Saturday will not have done anything to inspire public confidence.

“Families will be left wondering about the safety of their children and relatives, and we could see attendance figures drop when term restarts as families are left guessing about what is safe and what isn’t.

“We have already recommended that the Government removes the threat of attendance fines for families this term. Now we are heading back into lockdown rather than out of it, as many of us had hoped by now, the Government absolutely must take fines off the table.”

The Department for Education (DfE) has said fines for parents who refuse to send their children to school will only be used as a “last resort”.

The latest DfE statistics show that the majority of secondary schools in England had at least one pupil self-isolating due to potential contact with a Covid-19 case inside the school on October 22.

Around 26% of schools said they had one or more pupils self-isolating due to potential contact with a Covid-19 case, compared with 21% the week before.

This is 55% of secondary schools and 20% of primary schools.

Around 10,000 pupils in state schools (0.1%) – excluding those on half-term – did not attend class on October 22 because they tested positive for Covid-19.

It could become more difficult to keep schools open if more staff fall ill and cannot come to work, Mr Whiteman has warned.

He said: “We want to see young people facing the minimum amount of disruption to their education as possible, so keeping schools open is the priority, but this must be done in a safe way.

“Additional measures will almost certainly be needed to ensure this so we are asking for an urgent review of the current guidance.

“The safety of both staff and pupils must be paramount. Ultimately, staff who fall ill will be unable to come in to work which will only make it harder and harder to keep schools open.”

A DfE spokeswoman said: “We are prioritising children’s and young people’s education and wellbeing, by keeping nurseries, schools, colleges and universities open.

“The chief and deputy chief medical officers have highlighted the risks of not being in education on their development and mental health.

“Schools should work with families to ensure children are attending full-time. As usual, fines will sit alongside this, but only as a last resort and where there is no valid reason for absence. “