has learned that Department for Education officials tackling the workload problem have agreed to meet representatives from the Unison, GMB and Unite unions to address the concerns of their 350,000 school-based members.
A record 43,000 teachers responded to the DfE's Workload Challenge, which was launched to help ministers understand why England's teachers have some of the longest working weeks in the developed world. The department intends to publish an "action plan" this month, and education secretary Nicky Morgan has vowed to introduce measures to reduce the "unnecessary and unsustainable workload" faced by teachers.
But a survey of more than 15,000 Unison members, conducted in the autumn term, found that 80 per cent were concerned about workload. Almost three-quarters (74 per cent) of respondents said they regularly worked unpaid overtime. Of these, four out of five (81 per cent) claimed they were forced to do so to cope with increasing demands on their time in school.
The highest proportion of complaints about workload came from finance staff (91 per cent), school business managers (88 per cent) and exams officers (88 per cent). More than a third of cleaning, catering and finance staff reported feeling stressed "most of the time" or "always".
"If everyone worked just their hours, nothing would be completed and pupils would suffer," one respondent said. "Too much goodwill is given for very little pay. Schools are demanding environments with increasing pressure to work beyond just support."
Jon Richards, Unison's national secretary for education and children's services, said long working hours were already a problem for non-teaching staff.
"If they are going to reduce the workload of teachers, who is going to do the work instead?" he added. "We are very pleased that the department has accepted our case that workload is an issue for school support staff as well as for teachers.
"As our surveys have shown, some groups of school support staff also work excessive unpaid overtime and their issues also need addressing. The department will also need to ensure that any changes to teacher workload agreed with the teaching unions do not just transfer problems to another staff group."
Sigrid Atherton, a learning support assistant at Martin High School in Leicester, said the workload for support staff at her school had increased in recent months. "We're the lowest paid people in the education system," she said. "They want more from us without any more pay."
The latest concerns over workload have surfaced after the DfE's decision last year to scrap the list of 21 tasks that teachers were banned from carrying out in school. These administrative and clerical activities include writing letters to parents, analysing attendance data and arranging cover for absent teachers.
The DfE argued that the list placed "artificial and potentially over-prescriptive limits on what a teacher can do", but Mr Richards warned at the time that its removal "could see teachers washed away in a flood of administration and bureaucracy, taking them away from their primary job of teaching children".
A DfE spokeswoman said a programme of action to address workload problems for all staff, including support staff, would be published shortly.
"We want to make sure all staff in our schools - including support staff - are able to focus on preparing children for life in modern Britain and are not over-burdened with unnecessary tasks," she added. "That is why we launched the Workload Challenge, which received responses from support staff as well as teachers and school leaders."