Teachers will come under much greater scrutiny from inspectors after Ofsted backed down in response to criticism of its “light touch” visits.

Classes at high performing primary schools are observed for an average of just three hours per inspection over one or two days, with lightning visits at some.

This will now increase “significantly”, although a spokesman would not be drawn on exactly how many hours it would entail.

All schools faced about 24 hours of lesson observation, spread across one or two weeks, until 2005 when the shorter inspections were introduced for the top 30 per cent of schools.

But they have sustained a barrage of criticism from schools, teaching unions and MPs, who claim inspectors no longer spend enough time in classrooms to assess teachers accurately.

Some complained that lessons were observed for only 10 minutes each, with inspectors relying too heavily on self-assessment and data such as exam results.

However a Whitehall source said teachers had previously moaned about being inspected too much, adding: “Either we’re accused of being steamrollers who are ruining teachers’ lives or we’re pussy cats not doing our jobs properly.”

Despite the average lesson observation of 3.25 hours at primaries and 9 hours at secondaries, it is not uncommon for schools with previous good Ofsted reports to have just an hour spread across several classes during their next inspection.

An Ofsted spokesman said the decision to increase the number of hours inspectors spent in the classroom was part of wider proposed reforms that would be unveiled on Monday.

He said: “We want to go in and address underlying problems in failing schools, and we need the resources to do that. We want to focus on making a difference in poor schools.”

Addressing MPs on the Children, Schools and Families committee yesterday, Christine Gilbert, the Chief Inspector of Ofsted, said: “Next week we are going to start consulting on changes to school inspections.

“We are unique in having the power to enter schools and classroom, and I can assure the committee that any new arrangements will make the most of this.

“This means inspectors may spend more time than they currently do in classrooms, inspecting the quality of teaching and the impact it is having on the quality of lessons and children’s learning.”

Despite the longer ‘light touch’ inspections, Ms Gilbert said Ofsted still intended to concentrate its attentions on schools that were doing badly.

She said: “We want to focus less on organisations that are good [with more] inspections where there is greatest need and inadequate provision.”

The chief inspector said there had been considerable improvements over the last 10 years but admitted that progress had stalled. She added that some of the schools with the worst GCSE results still had good leadership and management.

Barry Sheerman, the committee chairman, expressed surprise and disappointment that neither Ms Gilbert, nor her key advisors, had read an influential and widely-anticipated report published by his committee this week, that criticised the level of testing in schools.

He said: “I’m a little bit worried that you seem to have a rosier view than what’s going on out there than we have. I wish we were following you into the cutting edge rather than you following us.”

The increase in classroom observation as part of inspections was welcomed by teaching unions.

John Dunford, general secretary of the Association of School and College Leaders, said: “Following the introduction of shorter inspections, the focus has moved from classroom observation by inspectors to a detailed inspection of data and school leadership.

“Increasing the amount of lesson observation during inspections will help to give inspectors a more rounded view of the school.”

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