Staff at Caldicot secondary school say they 'do not feel safe' going into work and are calling for 'better support'.
There will be two walkouts this month followed by a further four days in October.
The NASUWT, Teachers' Union said negotiations with the school with regards to ongoing concerns about 'adverse management practices' had not been resolved. The Union claims it is affecting the health, safety and welfare of its members and the pupils in their care.
In the strike ballot, 85% of members voted to support strike action and 92% voted to support action short of strike, which includes the refusal to teach pupils who pose a risk to staff. Negotiations have been ongoing since 2019.
"Caldicot School has failed in their most basic commitment to support teachers to teach," according to NASUWT General Secretary Dr Patrick Roach.
He added; "Teachers cannot teach and pupils cannot learn, in an environment where there is disruption and violence.
"Poor pupil behaviour cannot be explained away by attributing it to a teacher’s ability to plan and deliver lessons appropriately, something which parents and the public accept."
The Union says by choosing to strike, members are 'sending a clear message' and 'will not tolerate threats to the health, safety and well-being of themselves or their pupils'.
The NASUWT claims there has been a 'growing trend of violence in schools since Covid' and that 'Caldicot was having problems before the pandemic'.
"Doing nothing is not an option," according to NASUWT National Official Wales Neil Butler.
He added; "The dispute can be easily resolved but we need some proactive intervention by Monmouthshire Council to deal with this issue.”
Monmouthshire County Council is 'disappointed' over the NASUWT's decision to proceed with strike action. A spokesman said: "(We) recognise that this action, so close to the start of term, will cause concerns for parents and learners."We have been working closely with both the school leadership and NASUWT to help them resolve the school based issues that have led to this decision."We will continue this work and to advocate for a swift resolution on behalf of all of the school's learners."
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