Teachers’ leaders have warned that a third wave of Covid cases could threaten schools after Easter unless strict safety measures to prevent transmission remain in place.

The NASUWT teachers’ union has said that ahead of pupils’ return for the summer term, the government must not “remove or water down the current guidance”, such as the need for secondary pupils to wear masks in classrooms and other areas of school where social distancing cannot be maintained.

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Patrick Roach, general secretary of the NASUWT, said: “There is a real risk that the success of the vaccination programme to date, the easing of the lockdown and the reduction in current case numbers could lead to ministers being tempted to relax the Covid control measures in schools after Easter.

“In our view this would be a mistake. Ministers must model the behaviour they want to see in maintaining discipline and adherence to Covid safety measures.

“Relaxing the rules in schools would send a message to pupils and parents that the threat of Covid has passed at a time when extreme caution is still needed.

“We are not out of the woods yet and maintaining the highest levels of Covid security in our schools is critical as we move into the new term in order to protect the safety and health of teachers and learners,” he added.

The government has said it will review the rules on face coverings for secondary pupils over Easter, and the NASUWT has said it is concerned that with the easing of the third national lockdown, ministers may decide to relax the guidance.

The union says it believes this would undermine Covid safety and that pupils would be less likely to stick to wider safety controls in schools as a result.

It added that teachers strongly supported the use of face coverings by secondary pupils, with three quarters of NASUWT members who responded to a recent union survey saying they were in favour of secondary students wearing masks.

A further 67 per cent in a separate Covid safety survey said they supported the continuation of the guidance on face coverings into the new term.

And nearly 7 in 10 - 69 per cent - of respondents to this survey said they were concerned that the planned relaxation of lockdown would encourage less compliance with safety measures in their school next term.