Progress in raising school standards has “stalled”, amid fears that the attainment gap between rich and poor shows no signs of closing, the Chief Inspector of Schools suggested yesterday.

Christine Gilbert, the head of Ofsted, said it was unacceptable that 20 per cent of pupils still failed to master basic English and maths when they left primary school, while 10 per cent of 16 to 18-year-olds who dropped out of education were not in work.

The link between these two groups of underperformers was very strong and was showing no sign of weakening, she said. “We are not seeing enough movement there. The gap between the ‘haves’ and the ‘have-nots’ is not reducing quickly enough,” Ms Gilbert said.

“We think standards have stalled and we think we need to accelerate improvement, and we are looking at ways of doing that.”

Ms Gilbert’s comments appear to contradict claims by ministers of “unprecedented improvements” and a continual and “unarguable evidence of rising achievement” in school standards.

They come after research from the Conservatives suggesting that the school system is dividing children along social and economic lines. Fewer than a third of children in the most deprived 10 per cent of households in England gain at least five GCSEs, including English and maths, at grades A* to C. In those areas that make up the richest 10 per cent, more than half do.

Ms Gilbert, outlining radical reforms to England’s school inspections, said that they would be more tailored to the performance of individual schools, with greater focus on underperforming schools. Rather than study overall or average school performance, inspectors would focus more on the progress made by different groups of children, including the weakest and the most vulnerable as well as the brightest.

Under the reforms, failing schools will be monitored two or three times a year. Schools judged as “satisfactory” will be inspected every three years, unless they are struggling to improve, in which case they will receive inspections every 12 to 18 months.

The best schools will be subjected to a “light touch” inspection every six years, with a short monitoring “health check” after three years.

Ms Gilbert said that GCSEs and national curriculum tests results may play a greater part in inspectors’ judgments in future. Inspectors will also take more account of the views of parents in deciding when a school needs to be inspected, through conducting regular surveys.

Pupils will also be surveyed regularly. In addition to being asked how happy, healthy and safe they feel, they may be asked how bored they are at school, Ms Gilbert said.

A consultation on how Ofsted will fulfil a new government requirement to measure child wellbeing will begin over the summer.

Ms Gilbert said that the inspectorate would trial “lightning” inspections, in which teachers would receive no warning before a visit, so that Ofsted could “see the school as it really is”. Schools currently receive two days’ warning of an Ofsted inspection.

Inspectors are likely to spend more time observing lessons, but no inspection will last longer than two days.

Teachers criticised the proposals, which are open to consultation until August 11. Christine Blower, acting general secretary of the National Union of Teachers, said that the “punitive” inspection system would lead staff to resign. “I can see no virtue in nonotice inspections. Schools will feel that an inspection visit is the equivalent of Russian roulette, and inspectors could visit when half the school is on a school trip,” she said.

Nansi Ellis, of the Association of Teachers and Lecturers, questioned the idea of enabling parents to trigger an inspection. “We would like parents to take any concerns about a school to the school itself in the first instance, with the confidence the school will sort out any problems,” she said.

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