More than 150 colleges will need to improve in the eyes of Ofsted or see their rating downgraded, under proposals by new chief inspector Sir Michael Wilshaw to toughen criteria for “outstanding” grades and abolish the “satisfactory” rating. The “outstanding” grades of about 50 colleges - more than half the total - are at risk.

Sir Michael said the changes reflected his determination to raise the quality of education for young people and adults. Hundreds of private training providers and adult education providers are also likely to be affected.

The proposals, put out to consultation yesterday, would mean it is impossible to achieve an “outstanding” grade without being rated as outstanding in teaching, learning and assessment - a move that could have a major impact on many colleges that currently enjoy the top grade. The reforms will also introduce no-notice inspections across the board from September, to see “what providers are really like”.

“I have started primarily with a drive to improve the quality of teaching, because good teaching is at the heart of a good education,” Sir Michael said. According to a reading of the inspection reports of the 89 outstanding colleges, about 50 of them would be at risk if they have not improved the standard of teaching and learning since they were last inspected.

The move comes after last year’s Ofsted annual report revealed that no college had been rated “outstanding” for teaching and learning over a 12-month period, despite five gaining the overall grade 1 rating. Ofsted’s director of learning and skills, Matthew Coffey, said there was a lack of consistency and that lesson observations in colleges were “over-generous”.

The Institute for Learning, the professional body for FE teachers, supported the change, although chief executive Toni Fazaeli said teachers themselves should be trusted to lead the improvement. “We want to look at ways in which teaching professionals can be more empowered and take ownership over their own development, so we expect some new and challenging conversations ahead,” she said. But the Association of Colleges said that Ofsted was overlooking colleges’ work with some of the country’s most challenging students.

Sir Michael also focused on the 180 private training providers, 61 adult education providers and 114 colleges - responsible for educating more than 1.1 million students - which were rated “satisfactory”. For several years Ofsted has drawn attention to the numbers of colleges that are “stuck” on a satisfactory grade: 69 colleges were satisfactory for two inspections running, including 29 that have not improved their grade over three inspections.

“This cycle of mediocrity needs to change,” Sir Michael said. “I am determined to achieve a step-change in ambition and expectation across the board, but particularly in colleges and providers that are not yet ‘good’.”

Under the new rules, the “satisfactory” grade will be renamed “requires improvement” from 1 September and recipients will only have between two and three years to achieve a “good” rating before they are downgraded to “inadequate”. That is because the inspection cycle for these colleges and training providers will be shortened to between 12 and 18 months, and after the third inspection without improvement they will automatically drop a grade. Providers that have a “satisfactory” rating on 31 August will be considered to have had their first strike already.

Ofsted aims to address its concerns about the quality of internal lesson observation by requiring colleges and training providers to supply anonymous information about the outcomes of performance management for all teaching staff. These will not be published, but will be used to assess how an institution’s managers encourage improvement.

The move is likely to intensify internal tensions within colleges over lesson observation. For several years it has been one of the main concerns of activists at the University and College Union’s annual congress, where they argue that it is used punitively and facilitates bullying. An increasing emphasis on these mechanisms to secure good Ofsted grades is likely to lead to further conflict.

Sir Michael appealed to college staff to support his reforms, however. “If I am to succeed in my ambition, I need the support of those of you who are equally passionate about improving our education system, especially those of you who are parents and those of you who work in education,” he said.

THE NUMBERS

89 Colleges are ‘outstanding’.

50 of these are not rated ‘outstanding’ for teaching and learning.

114 Colleges are ‘satisfactory’.

29 have failed to improve their grades over three inspections.