Secondary schools should be able to turn away pupils who refuse to wear masks, a teaching union has said.

The call comes as staff prepare for the part-time return of S1-6 students from March 15. 

Most are currently learning remotely in a bid to contain the spread of Covid-19.

Plans for the next phase of re-opening Scotland's education system - which will also see P4-7 pupils go back full-time - were announced earlier this week by Nicola Sturgeon. 

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The First Minister said they were based on continued declines in infection rates, test positivity and hospital admissions. 

But with schools set to host pupils in significantly greater numbers, the Government faces growing pressure to strengthen guidance aimed at keeping classrooms and corridors safe.

HeraldScotland: Nicola Sturgeon announced plans for a fresh wave of school re-openings earlier this week.Nicola Sturgeon announced plans for a fresh wave of school re-openings earlier this week.

In their latest recommendations, members of the Advisory Sub-Group on Education and Children's Issues said all secondary age youngsters, and not just those in S4-6, should be required to wear face coverings throughout the day.

The advice also states that two-metre physical distancing should continue among high school pupils and staff.

However, it refers to a potential relaxation of arrangements on school transport, as well as during outdoor activities and learning. 

Ministers have said they will publish updated guidance next week.

Seamus Searson, General Secretary at the Scottish Secondary Teachers' Association, said schools should be able to refuse entry to those who fail to comply with face covering requirements and other Covid safety measures.

"It's going to be one hell of a struggle to get pupils to wear masks in secondary school and, equally, to ensure they maintain the two-metre physical distance," he added. 

"I'm pleased the Government is looking to take every possible measure to keep everybody safe. 

"But we still need to have that support for schools to be able to say to a pupil that if you're not going to abide by the guidance, we're not going to have you here...  That's something we've argued for long and hard.

"Before, if a pupil was ignoring the guidance on masks, staff were just accepting it."

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Mr Searson said there was growing worry over the prospect of accommodating pupils during the week and continuing remote learning at the same time.

"The other issue is S1-3 pupils, who aren't going to be in school for most of the week - it might only be a day a week at the very most," he added. 

"It's going to be a big headache for schools to organise. And you're going to have schools berated by parents saying, 'the kids up the road are in school three days a week, why are mine only in one day a week?'

HeraldScotland: Most pupils are learning remotely as part of an effort to contain the spread of Covid-19.Most pupils are learning remotely as part of an effort to contain the spread of Covid-19.

"Parents of younger secondary pupils will need to be told that, because of the drive to have the seniors in, their engagement in school will be superficial. It might not even be continuous teaching. For example, it might simply be talking to them about how they're doing.

"In terms of S1-3s in school, you might be looking at having them outdoors as much as possible, which would at least mean they'd get to be with their friends.

"That's going to mean pressure on some teachers but what goes on inside school buildings would then be much more controlled."

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EIS General Secretary Larry Flanagan said his union welcomed "the new guidance on all secondary pupils wearing face coverings whilst in school, and indeed the introduction of 2m distancing amongst pupils". 

But he added: "It is important that the reasons for these new mitigations are fully explained to students to support their compliance with the measures, which are designed to make school buildings safer for everyone."

A Scottish Government spokeswoman said: "When secondary schools return on March 15, face coverings should be worn by pupils at all times, unless exemptions apply.

“Our guidance is clear that schools can take appropriate action, as is usual, if there are any concerns about a child or young person behaving or acting in a way which doesn’t align with school policy or procedure. Exclusion from school should continue to be a measure of last resort, in line with agreed national policy.”