HUNDREDS of Scottish pupils are expected to skip their classes on Friday afternoon as part of a UK-wide “strike” over climate change.

But any teachers who encourage their charges to take part in the demonstration could risk disciplinary action, the leader of one trade union has warned.

Protests have been organised in Glasgow, Edinburgh, Forres, Fort William and Ullapool.

Many parents of children who want to strike have used a draft letter written by Youth Strike 4 Climate, one of the groups supporting the UK Student Climate network.

It tries to explain to teachers why they have given their permission: “I’m aware of UK law that permits parents to only give permission for their child to miss school on medical grounds or in a few other cases, one of which is under ‘exceptional circumstances’.

“My view is that having only 12 years left to cut CO2 emissions by 50%, as per the latest UN IPCC report, is pretty dire and exceptional circumstances to find ourselves in. And it in this light that I’m giving my child permission.”

It continues: “I support her to attend the youth strike as part of active civic engagement, which is a core part of the curriculum. People under 18 years can’t vote, but with more of their life in the future, rather than the past, it’s they who are most affected by climate breakdown.”

Seamus Searson from the Scottish Secondary Teachers’ Association said the strikes posed a dilemma for schools. Any staff member not telling pupils to not miss class could, he said, find themselves in trouble with their employer.

“They put themselves in a real dangerous position because they’re breaching the terms of their contract. If they were to promote this or encourage youngsters to go on strike they could be disciplined, they could lose their job over it.”

But, he added, “the right to protest and campaign on things should be among all the other things that youngsters are supposed to learn while at school”.

“We can’t promote this but it may be something we need to think about for a wider discussion,” he said.

Organisers were inspired by Greta Thunberg, the 16-year-old Swedish activist who last August refused to attend school so that she could protest.

11-year-old Finlay Pringle told the Sunday National: “The important thing is that we are spreading the message along with all the other kids in the world that we need to do something about climate warming now.”

Holly Gillibrand, 13, will be missing classes at her Fort William school for the sixth time: “The planet is in trouble,” she said. “We need to stop subsidising fossil fuels and reduce carbon emissions to zero by 2025.”

A spokeswoman for Extinction Rebellion, who are offering help to the protesters, said: “We fully support the hundreds of pupils and students across Scotland who will be striking school and university on Friday to demand policy makers face facts and take action in the face of catastrophic climate and ecological chaos.

“It is our children and grandchildren’s futures that we’re endangering, and we must act now if we are to slow down the sixth mass extinction which science shows has already begun.”

A Scottish Government spokesman said: “We believe climate change is an extremely serious issue, but we do not encourage absence from school during term time.”

Last week the UK Met Office warned global warming could temporarily hit 1.5C above pre-industrial levels for the first time.

A second day of action is due to be held on March 15.