Three Norwich-area schools are among 11 across the county that have been told that they are so good that Ofsted inspectors will not be visiting them.

The schools received letters 'out of the blue', telling them that they either would not be inspected until at least summer 2012 - or, in the case of two outstanding schools, only if 'further information raises concerns'.

Tony Hull, headteacher at Costessey Junior on Three Mile Lane, rated 'good' in November 2007 and told this week that it would not need a new inspection until at least summer 2012, said: 'I take this as further verification confirming our self-analysis that things are at least good or outstanding.

'It's good to know that the authorities agree with us. Although the pressure of an inspection is removed, the pressure remains every day because the staff want to do a good job.'

Nightingale Infant on Nightingale Drive in Taverham and North Walsham Infant on Manor Road were the two outstanding schools to get the good news.

Clare Fletcher, headteacher at North Walsham Infant, said: 'The letter came out of the blue. In some ways the staff were disappointed, because they have done even more good things since the last inspection. But they were also relieved because of the stresses it can cause.'

Ofsted is able to examine from afar the paperwork and data of good and outstanding schools. If there are no signs of deterioration, it puts off a return visit - enabling it to concentrate on schools that are satisfactory or worse.

Mrs Fletcher said: 'It's a really good system because Ofsted doesn't need to keep on revisiting schools where there's a proven track record of success.'

The other good schools getting letters informing them that they would not be visited 'any earlier than the summer term 2012' are:

? Astley Primary, Melton Constable (last inspected June 2008)

? Blenheim Park Primary, Sculthorpe (September 2007)

? Erpingham Primary, near Aylsham (January 2008)

? Happisburgh Primary (June 2008)

? North Elmham Primary, near Dereham (February 2008)

? Poringland Primary (June 2008)

? Scole Primary, near Diss (March 2008)

? Worstead Primary, near North Walsham (June 2008).

In their letters, Ofsted chief inspector Christine Gilbert said: 'I am pleased to inform you that our interim assessment shows that the school's performance has been sustained and that we can defer its next full inspection.

'As a result, the next inspection will not take place any earlier than the summer term 2012 unless we receive information in the course of the coming year that causes us to inspect earlier.'