Ofsted claims its plans to overhaul school inspections are being opposed by “powerful vested interests”.
The watchdog is developing a new framework that will be used to inspect schools from next September.
It will place a greater emphasis on how schools deliver the curriculum and has been seen as a crackdown on “exam factory” schools that place too much emphasis on results.
But concerns about the changes have been voiced by a growing list of parties including education secretary Damian Hinds, teaching unions and a prominent academy chain.
Now, in an article for Tes today, Ofsted’s director of strategy, Luke Tryl, has hit back, writing: “I’m aware that there are powerful vested interests against change.
“While most heads and teachers we’ve spoken to welcome a refocusing on the substance of education, and the curriculum, there are a small minority of heads who hide behind Ofsted as they impose unreasonable practices on their staff.
“In other cases, a change in our focus will undoubtedly expose the emperor’s new clothes, those who have trumpeted stellar headline results that are built on the back of curriculum narrowing and teaching to the test.”
Yesterday Teach First chief executive Russell Hobby warned that the changes would be incompatible with having a neutral stance on teaching methods and curriculum design.
And Professor Dame Alison Peacock, chief executive of the Chartered College of Teaching, said they would leave school leaders "in fear and dread".
The latest prominent figure to warn against the overhaul is Dame Rachel de Souza chief executive of the Inspiration Trust academy chain who says Ofsted is right to focus on the curriculum but fears the extra burden a new framework will bring.
“A new framework feels like it will cause additional work,” she told Tes.
Tensions have also been rising between the Department for Education and Ofsted about the inspection framework.
Education secretary Damian Hinds has repeatedly failed to back the inspectorate's plans and raised concerns that they might increase teachers' workload.
Meanwhile, the NAHT headteachers' union has urged chief inspector Amanda Spielman to "pause" the changes.
But Mr Tryl argues today that “this change can’t wait”.
“The role of inspection should be to balance performance data, to look not just at what young people achieve, but how,” he writes.
“And crucially to tackle the perverse incentives that come from any data-driven accountability regime, no matter how perfect…
“Another year of the current system is equivalent to 8.5 million pupil years across all our schools. Another year of a system that we agree isn’t working as it should for children or teachers.”
He also addresses a controversy sparked by Sean Harford, Ofsted’s national director, education, who wrote on Twitter that working together with the National Education Union was “impossible” because it wants the inspectorate to be abolished.
Mr Tryl says: “To be clear Ofsted will always engage with any teaching union and listen to the concerns of their members, whether you call for our abolition or not.
“But I will say this: those unions who are having actual influence in shaping the new framework are those who, yes robustly challenge us with the concerns of their members, but who also provide constructive suggestions for how we improve our current practice.”