A south Norfolk headteacher has demanded answers from Ofsted after inspectors downgraded his school from being 'good' to 'satisfactory'.

Neil McShane, of Attleborough High School, which was judged as good at its previous inspection in 2008, said he was 'surprised' at the overall rating despite inspectors grading the majority of lessons as being of at least good quality.

The judgement also follows the school becoming only the twentieth in the country to be re-accredited with the national Challenge Award following an inspection by the National Association for Able Children in Education (NACE) which acknowledges schools that provide excellent challenge for all students and meets the needs of the most able.

Staff at the high school have submitted their concerns to Ofsted about the inspection process.

Mr McShane said: 'We are very proud to report that over three quarters - 76pc - of all lessons were graded by Inspectors as 'good' or 'outstanding' and none were judged as less than satisfactory. Given this impressive evidence, we are surprised that the overall judgement is not higher and Ofsted are already conducting an investigation into our concerns about the process.'

A spokesman for Ofsted said it was unable to comment on individual cases.

Attleborough High took part in a pilot inspection on May 23 and 24, which involved the observation of about 18 hours of teaching, including 26 teachers, as well as the analysis of 297 parent questionnaires, alongside 77 from staff and 160 from students.

According to the subsequent report, inspectors found the school provided a 'caring and supportive' environment for students, while Mr McShane and his team were making a 'concerted approach' towards improvements.

On teaching, it said: 'Inspectors observed lessons where students were fully engaged and enthusiastically learning. There are, however, lessons where teaching does not ensure that all students are totally involved in what they are doing in all parts of the lesson. Sometimes the work is too hard or too easy for individuals and sometimes students are not sure how to improve their work.'

It noted that a minority of students felt their classes were disrupted by poor behaviour when the teaching did not capture students' interests, and while most believed incidents of bullying were dealt with effectively, a minority thought the school did not deal with all cases well.

The report added that the curriculum 'adequately helps develop students into confident, thoughtful and independent young people' and the school's overall performance in GCSEs had been in line with national averages, with performances in its specialist subjects of maths and computing being strong in the last few years.

Inspectors have recommended that students' progress is improved by ensuring teachers retain high expectations of what the youngsters can achieve, set work matched to students' abilities, make sure all lessons are engaging and promote good behaviour.

To read the full report, visit www.ofsted.gov.uk