Nearly a third of teachers could escape having lessons observed by inspectors under a major expansion of Ofsted’s ultra-light touch programme, the new chief inspector has revealed.

Christine Gilbert, giving her first interview since becoming head of Ofsted three weeks ago, told The TES that 30 per cent of schools would qualify for the programme from April. Since September, a fifth of schools - those judged to be performing well - have been subject to one-day visits by single inspectors with few if any lesson observations.

Ms Gilbert revealed Ofsted has considered extending the ultra-light inspections even further to more than 30 per cent of schools. “There has been some debate in here,” she said. “But people are worried about whether real rigour can be maintained with one inspector in one school for a day and part of that day would involve writing a report up.”

The shorter inspections mean school self-evaluation and test results become much more important in determining Ofsted verdicts.

This week, Lord Adonis, schools minister, and Beverley Hughes, children’s minister, have written to every local education authority demanding they take urgent action to improve primary and secondary results.

The blunt letter warns there are still too many schools letting down pupils with “unacceptably low” expectations of results. Ms Gilbert believes that the present plateau in results can be resolved by personalised learning.

She has spent eight months heading the Government’s review on the concept.

She says its final report, due in December, will not be “heavily prescriptive” and need not place an extra burden on teachers. “It isn’t 30 different programmes per class, which any teacher would feel despair at the thought of,” she said. “It is focusing on individual needs.”

When the ultra-light touch inspections were announced earlier this year, Ofsted said it was likely inspectors would briefly visit one or more lessons but might not observe any.

John Chowcatt, general secretary of inspectors’ union Aspect, said: “It is important that the emphasis is still on teaching and learning which is the key activity in schools. We want Christine to ensure that the system remains rigorous because very effective schools can slide in their performance. Movements in key personnel, not just headteachers but middle mangers, can lead to sudden deterioration.”

Asked if the new system meant the inspectorate was losing its teeth, Ms Gilbert said inspectors were going into lessons. But she said: “I think we have got to take time to review the way this is being implemented.”

John Crossley, head of William Allitt school in Swadlincote, Derbyshire, experienced one of the first ultra-light inspections in October and welcomed the change. But he said some staff felt they were judged too quickly by an inspector who was only in lessons for 10 minutes.

Christine Gilbert interview, 3 Ministers’ letter, 2