Ofsted intends to reintroduce inspections to "outstanding" schools and place thousands of extra schools in a legal category that would allow ministers to order them to become academies.
The proposal for top-rated schools in England could be seen as an embarrassing U-turn for Michael Gove, who originally came up with the idea of exempting them from further regular inspection.
But the Westminster education secretary is said to be supportive of the plan to redefine schools receiving a grade 3 inspection - known as "satisfactory" - as schools that "require significant improvement", a change that could put rocket boosters on his academies revolution.
On the basis of 2010-11 figures, the reform would boost from 437 to 6,554 the number of schools with Ofsted verdicts that leave them open to ministerial intervention and academy orders.
The change was part of measures announced last week by Sir Michael Wilshaw, Ofsted's new chief inspector, which he wants to introduce from September.
They include inspectors checking heads' decisions about performance management for teachers and their links to pay, and no-notice inspections for all schools.
The watchdog also plans to make outstanding teaching a prerequisite for an overall outstanding verdict and to deem only good and outstanding schools as providing an "acceptable standard of education".
Taken together, the measures are likely to be seen as a huge increase in pressure on schools, heads and teachers.
Sir Michael argues the changes are needed to transform "poor performance" in schools, strengthen communities and improve economic competitiveness when 1.5 million youngsters are outside education and employment.
Heads' leaders were disappointed by the chief inspector's focus on poor leadership earlier this week and warned that "constant criticism and abuse" would lead to an "exodus" of headteachers from the profession.
But Sir Michael said that there had been no deliberate shift to more critical language and that it was important that there was good morale in teaching.
"Morale comes not just through better pay and conditions and so on, but through knowing that you are working in a good school that is attempting to do good things by children," he said. "It is important that we sometimes say tough things - that leadership is vital in changing the culture of a school and that, if heads can't improve things over a period of time, that issue needs to be addressed."
The chief inspector said that the idea that renaming and changing the legal status of the satisfactory inspection grade could lead to more schools becoming academies "didn't enter my head". Using academy status as a solution for schools with the new "requires improvement" grade was an issue for government and not Ofsted.
Ofsted is proposing that from September:
- All schools will have no-notice inspections.
- Outstanding verdicts will not be given to schools without outstanding teaching.
- The "satisfactory" (grade 3) judgement will be renamed "requires improvement", a title that will also replace the current "notice to improve".
- Any school deemed as "requires improvement" for a third consecutive time will go straight into special measures.
- Schools will be fully reinspected 12-18 months after a grade 3 verdict, giving them a maximum of three years to reach a "good" standard.
- Only "good" and "outstanding" schools will be deemed as providing an "acceptable standard of education".
- Schools with "requires improvement" verdicts will be legally defined as "requiring significant improvement", meaning that they are, like schools in special measures, open to ministerial intervention and academy orders.
- Inspectors will be provided with the latest, anonymised information on the performance management of all teachers in a school.
- Ofsted is already talking to the government about introducing more inspections for outstanding schools and wants to introduce clearer, more "blunt" language in its reports.