Union delegates will be asked to back calls for a formal weekly limit on the number of working hours for teachers.
Kevin Courtney, joint general secretary of the NEU, said “we are reaching a point” where such a limit needs to be brought in.
A motion on workload, proposed by the Kirklees branch, calls for the removal of a clause in the teachers’ pay and conditions document that says they “must work such reasonable additional hours as may be necessary to enable the effective discharge of the teacher’s professional duties”.
And a proposed amendment to a motion on "fair pay for teachers" says the clause should be removed from the document – and replaced with “a clear limit on hours teachers can be expected to work”.
Limits on working hours
Last year, Department for Education research found that classroom teachers and middle leaders work an average 56-hour week.
Mr Courtney said there has been a debate within the teaching profession about whether to limit unnecessary tasks, such as producing evidence for "bureaucrats" by “asserting professional control” or introducing a specific limit on working hours.
He added: “I think we are now reaching a point where people think that in order to get the former, the professional control, we have to have the latter.
“If there was an upper limit then headteachers would be forced to think about how they use teacher hours and they would be forced to discuss that with teachers in schools.
“In those conversations, teachers would be saying ‘well, look, I’m up to this hours limit, what I want to spend my time doing is preparing exciting lessons, and that would mean that I can’t do that evidence for you’.”
Mr Courtney said there would have to be discussions about what any upper limit should be, but said: “We think we know that teachers are working during the school holidays, so that we believe that they may well be over the 48 hours European working time directive limits, so we would certainly want an hours limit that was going to reduce workload from where it is at the moment.”
He cited the McCrone Agreement in Scotland, which limits working time to 35 hours a week, although he acknowledged that teachers often choose to work longer.