Teachers at more than 20 schools have voted formally for industrial action in protest at changes to senior staff pay which will cost individuals up to Pounds 10,500-a-year.
Members of the National Union of Teachers staged a one day walkout at a further two secondary schools this week, Todmorden in Calderdale and Prestwich in Bury, over the replacement of management allowances with teaching and learning responsibility payments.
Todmorden, whose headteacher Ed Collins is a member of the Association of School and College Leaders executive, was expected to be closed yesterday to all pupils apart from those in the sixth form and those taking scheduled exams.
The school is planning to replace six head of year teaching posts with the same number of non-teaching pastoral managers who will be paid only in term time. The special needs co-ordinator will become a non-teaching post.
Protests against the changes hve now taken place at eight schools - seven secondaries and one primary.
Teachers at Plumstead Manor in Greenwich, south-east London, held a second strike this week.
The NUT has approved ballots for strike action in 40 schools. With 23 results in, all show a majority in favour of action.
It expects about 50 schools will see strike action as a result of the changes.
Teachers at about 250 schools have indicated through informal votes that they are in favour of action.
Most disputes involve schools trying to create new staffing structures with fewer pastoral posts, such as head of year and a reduction in the number of heads of departments. Some primary schools have also opted to cut the number of subject co-ordinators.
Under the changes, all schools in England were expected to complete a review of their staffing, detailing who would get the new TLR payments, by the end of December.
But John Dunford, general secretary of the Association of School and College Leaders, said the process had been delayed in some schools because of appeals by staff who are losing out. A small number missed the deadline because they did not have enough time to work though the complex issues, he said.
Unlike the management allowances, which are worth pound;1,163 to pound;10,572 a year, TLRs are focused solely on raising standards and cannot be awarded for administrative tasks.
The changes were agreed between the Government and the unions in its social partnership - the NASUWT, Association of Teachers and Lecturers and the Association of School and College Leaders - but do not have the backing of the NUT or the National Association of Head Teachers.