Disputes over pupil discipline and school management have prompted the second largest teaching union to ballot for strikes at three Midlands schools.
Members of the National Association of Schoolmasters Union of Women Teachers at Barr Beacon language college in Walsall went on strike on Wednesday causing a bitter row with governors.
Pattie Lane, chair of governors at the college, said pupils were becoming pawns in an attempt to force the school to re-instate NASUWT representative, Tony Parker, who was suspended before Christmas.
But Chris Keates, NASUWT general secretary, described her remarks as a "gross distortion". The suspension of Mr Parker was not the main issue.
Striking was the only option because an action plan to address discipline had not been implemented, she said.
In the past year one pupil has been accused of a stabbing in a fight outside school and others have put tripwires on stairways and corridors at ankle, neck and eye level.
Alderwasley Hall school in Belper, Derbyshire, has avoided further action by the NASUWT after agreeing that a 15-year-old boy will not be taught by members, who make up 18 of the school's 19 classroom teachers.
The union held a one-day strike at the independent boarding school for autistic pupils in November, after a member needed hospital treatment following an assault by the boy, who had a history of attacking adults.
Brian Jones, from the school's owners, Senad Group, said the boy had pushed rather than assaulted the teacher and would continue to have the school's support.
Meanwhile at Heritage school, Clowne, also in Derbyshire, the union has agreed to suspend strike action over the denial of upper-pay-scale rises, worth Pounds 1,128, to four of its members until Tuesday while talks take place.
* As The TES went to press, crisis talks were being held to try to avert a strike ballot of nearly 40 National Union of Teachers members at Leicester's 1,700-pupil New College, following 12 assaults on staff between September and December last term.