Fewer than one in five parents realise that “outstanding” schools are exempt from reinspection, a new Ofsted survey reveals.

The figures from the inspectorate’s fourth annual survey, published today, show that only 17 per cent of parents were aware that schools given the top inspection grade are not routinely revisited by Ofsted.

Almost three-quarters (72 per cent) of parents surveyed said that “outstanding” schools should be inspected as often as those rated “good” because standards can change quickly.

Ofsted: Let us inspect ‘outstanding’ schools

Inspections: More than three-quarters of schools lost their top grade

Curriculum: ‘Outstanding’ schools could be narrowing the curriculum

Ofsted has previously told the Department for Education that it wants the exemption on “outstanding” schools to be lifted.

Ofsted school inspections

Schools standards minister Nick Gibb told the inspectorate last year to inspect at least 10 per cent of “outstanding” schools.

Ofsted can inspect “outstanding” schools in response to concerns about a drop in standards or safeguarding.

It was revealed last month that less than a quarter of the “outstanding” schools inspected by Ofsted in the first term of this school year kept their top grade.

The inspectorate said that just 23 per cent of the 117 schools it had inspected from 1 September to 31 December retained their “outstanding” judgement.

“Outstanding” rated schools have been exempt from reinspection since 2012.

Last year the inspectorate warned the government that the situation was unsustainable after a National Audit Office report found that 1,620 schools had not been inspected for six years or more, including 296 schools that had not been inspected for 10 years.

In the Ofsted parents’ survey, nine in 10 parents knew the Ofsted rating of their child’s school or child care provider, although parents of secondary school pupils were significantly less likely to know the rating.

Three-quarters of parents continue to feel that Ofsted is a reliable source of information, and there has been a drop in the proportion of parents who feel Ofsted is unreliable - from 19 per cent to 16 per cent.

The survey, carried out by YouGov, also shows that six in 10 parents feel that Ofsted is a force for improvement and a trusted judge of standards.