Schools should stop employing so many support staff on temporary contracts, as they de-motivate staff and create instability for pupils, say new guidelines published this month.
The guidance for schools is the result of 18 months of negotiations between unions and employers on the new workload agreement. It also includes model job descriptions for four different levels of support staff and advice on training them.
A survey commissioned by Unison, the biggest support staff union, and The TES last year found that 40 per cent of school support staff were on temporary or fixed-term contracts.
The guidance says that far more staff should be offered permanent contracts and advises that, where they are not, the school should give a reason, and specify the likely length of the contract and the event that would lead to its termination.
Bruni de la Motte, a Unison national officer for education, said that although there was no compulsion for schools to follow the guidance she thought it would help make a difference to the problem.
"Schools are being told in no uncertain terms that this is not good practice and that the consequences are instability for pupils and insecurity for the workforce," she said.
The model job descriptions outline what would be expected of staff working in classroom support, administrative and technical roles at four levels.
For assistants supporting and delivering learning they are:
* Level one
These inexperienced teaching assistants would be supervised and trained and would not be left alone with a class. They could work one to one or with small groups of pupils and provide general clerical support for the teacher.
* Level two
These assistants would still be supervised and trained. As they gain further experience they could deliver pre-prepared exercises to groups of pupils as part of the numeracy and literacy strategies. They could also help with planning.
* Level three
Specialist assistants, working under guidance, could supervise classes when teachers are absent, become more involved in the delivery of lessons and planning, evaluate and keep records and specialise in a particular subject.
* Level four
Higher-level assistants would work under an "agreed system of supervision management" and could deliver lessons to whole classes alone, manage support staff and plan their own work.
Ms de la Motte said that the last month had seen an unprecedented level of activity from local education authorities in most areas of the country as they sought to implement the workload agreement.
But there were problems in Wales over a lack of funding and reports from her union's branches in the South-east suggested authorities and schools there had not been negotiating with it over new roles for support staff.
In a motion to be discussed by Unison's local government executive, the union's South-east regional council warns that many schools are "driving a coach and horses" through the agreement, by not consulting it over job descriptions and salaries for the new support posts.
It continues: "Unison is losing credibility with its membership for signing an agreement with little consultation that is not delivering any benefits in most branches, and, worse, is a step backwards in some cases."