Teachers have been forced to change the way they work more in the past five years than in the previous two decades, research shows.
The study, for the Association of Teachers and Lecturers, found policy had come full circle, with recent reforms reinstating what prescriptive initiatives, such as the literacy and numeracy strategies, had removed.
In the past month, the literacy hour has been all but abolished in its original form, with primary teachers being told to make their lessons more creative, using a variety of methods.
The research, by academics at York university, tracked the attitudes of teachers in 50 schools, initially studied in 1992-94. One Year 5 teacher observed that the literacy and numeracy strategies had been rigid in their objectives.
"That has gone now. The children can see the purpose of one lesson and the one before and the one coming next," she said.
A headteacher told researchers that the strategies cost teachers their ability to work flexibly and creatively. "It's gone full circle. Creativity and flexibility are being valued now, and a lot of the constraints are being removed by the Government because I think they've seen a lot was lost."
Teachers continued to oppose testing and league tables and wanted them abolished. They believed key stage 2 tests distorted work in the final year of primary school, and were stressful for pupils, particularly low-achievers.
However, teachers believed the quality of teaching and learning in primary schools was better than ever, enhanced by ICT and teaching assistants.
A Year 4 teacher described how she felt when her teaching assistant was away for a week. "It was a shock. It was like having your arm chopped off.
Right in the middle of the lesson you don't think and automatically look for reassurance from your support assistant."
But overall teachers' confidence levels, dented through the earlier stages of implementing reforms, were showing signs of recovery.
While many had initially reacted to the literacy strategy with hostility, with hindsight they believed their classroom methods had improved.
The study found the strategies had enabled teachers to reflect critically on their classroom practice.
It said: "Many seemed unable to change or challenge that practice until forced to do so by the introduction of a national initiative."
Nansi Ellis, the ATL's deputy head of policy, said the union believed it was the role of the profession and not the Government to decide what was needed in schools.
"Reflection brought on by constant criticism and shaming is unlikely to generate confident practice in the long term.
"The challenge is to develop a confident profession which can offer constructive analysis of governmental policy as well as develop its own pedagogy," the report said.
Mary Bousted, general secretary of the ATL, said: "Primary school teachers have been overwhelmed by a plethora of initiatives in recent times, from national assessment targets to curriculum reform."
She said that while there had been benefits from these strategies, over-testing "continues to have adverse effects on children's learning and teachers' well-being".
Coming Full Circle? The impact of New Labour's education policies on primary school teachers' work, by Rosemary Webb and Graham Vulliamy, from www.atl.org.uk