Heads, support staff and teaching unions are lining up to defend the agreement and rubbish NUT claims that it could lead to classes of 60 pupils.
David Hart, general secretary of the National Association of Headteachers, writes in a letter to The TES this week that the NUT's recent adverts attacking the deal are "misleading" and "distorted" .
He is supported by other pro-deal unions which are sending posters to every school to promote the agreement.
Pro-deal unions representing teachers and support staff have also advertised in this week's TES disputing the NUT's claim that the agreement will see assistants replacing qualified teachers.
The NUT opened the propaganda war in December, before the deal was finalised, when it placed an advert in The TES criticising the Government's negotiating position. Its latest advert quotes a member attacking the agreement.
This week the NUT released a survey of schools taking part in the Government's Pathfinder project to try out different ways of cutting workload.
Teachers who responded to the survey questioned whether support staff were capable of taking on some non-teaching roles, such as exams co-ordinator.
They agreed that the 32 Pathfinder projects had reduced workload, but were concerned at lack of training for support staff and asked whether the changes could be sustained once funding stopped.
Schools involved in the pound;4 million project were also concerned that the Government was pressing ahead with plans to allow "high-level" assistants to take classes before the trial was finished.
Pathfinder initiatives included a restructured school day; "flexible teaching centres" where larger groups are taught by one teacher plus support staff; and taking on a "floating" teacher to give colleagues non-contact time.
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