Schools watchdog Ofsted has begun an intensive week of inspections as it aims to discover why Norfolk has such a high proportion of under-performing schools.

Just 54pc of secondary school children, and 63pc of primary youngsters, in this county currently attend a good or better school.

Yesterday, as inspectors began their visits which are likely to include a number in the greater Norwich area, Ofsted said those figures were well below the national average and compared poorly with other similar local authority areas like Cornwall.

Sean Harford, Ofsted regional director for the East of England, said: 'It cannot be right that local authority areas with similar demographics – such as the size of the population and the levels of deprivation – have such varying levels of provision in schools.'

Poringland Primary, which was rated good in 2008, Stalham Community Infant School and Buxton Primary, which were both judged satisfactory two years ago, were the first to get visits yesterday and Ofsted said all inspections would take place at schools that were due to be assessed at some point this term.

One headteacher said a number of Norwich schools were bracing themselves for a call to say they were one of the county's 28 chosen schools.

He said staff would naturally be nervous about the arrival of inspectors.

'It's terrifying, Ofsted has got such power. If they give your school a judgement that's negative, it can have major, major long term consequences for a school,' he said.

Ofsted said the inspections aimed to get both a 'powerful snapshot' of how well schools in Norfolk were performing and a strong indication of the quality of external support and direction offered by the local authority. Schools subject to inspections as well as a number of others across the county will be surveyed on the help they feel they get.

Gordon Boyd, assistant director of children's services in Norfolk, said the local authority's role was inextricably linked with the work of the schools, which were responsible for their own improvement.

But he said he welcomed a chance to get feedback on the efforts it was making to try to push up standards as the 'champion of Norfolk young people.'

The individual school assessments will be published by Ofsted on its website over the next few weeks with a letter setting out the overall findings of the week to be made public at a later date.

Do you have an education story? Contact Victoria Leggett on 01603 772468 or email victoria.leggett@archant.co.uk.