A LACK of headteachers has been blamed for a decline in standards as new figures show rising numbers of primary schools are failing their children.

The inspection figures, released yesterday by education watchdog Ofsted, revealed a 32 per cent rise in primary schools in England placed on special measures during the past year.

Special measures is the inspectorate's lowest category.

The findings came as separate Government figures showed 520 nursery and primary schools - three per cent of England's total - had been forced to fill their headteacher posts on a temporary basis.

Mick Brookes, general secretary of the National Association of Head Teachers, said: "Schools without permanent leadership teams are likely to be struggling to raise standards. We must get this right quickly."

But an Ofsted spokeswoman said the rise could be due to the increase in schools inspected - 6,129 schools nationally in 2005-06, compared with 8,300 this year.

The spokeswoman said that by the end of this summer, 246 schools, or 1.1 per cent of all schools, were in special measures, compared to 208 schools, or 0.9 per cent, by the end of summer 2006.

She told The Northern Echo: "The proportion of schools inspected that went into special measures in 2006-07 was lower than in 2005-06 - 2.2 per cent in 2006-07, compared to 2.7 per cent in 2005-06."

In the North-East and North Yorkshire, ten schools had been placed in Ofsted's bottom category by the end of last month, compared to eight schools last year, according to the figures.

Nick Seaton, the York-based chairman of the Campaign for Real Education, a pressure group which campaigns for more choice and higher standards in state education, said the figures were concerning.

"It is extremely serious," he said. "After all the pressure that has been put on schools and all the extra money they are getting, the number in special measures should be falling, not increasing."

Among the schools listed as being on special measures is Darlington's Alternative Centre for Education, which used to be called the Pupil Referral Unit.

A council spokeswoman said Ofsted had visited twice since the school was put on special measures, last October, and had judged progress as satisfactory.

In North Yorkshire, three schools - Oakridge Community Primary, Airville and Mill Hill Community schools - are classed in the bottom category. There were two in 2005-06.

A spokesman for North Yorkshire County Council's Children and Young People's Service, said: "We are naturally disappointed that the number of schools in special measures in North Yorkshire has increased, although it is important to stress that this is still only three schools out of nearly 400."

In Durham, two schools were on special measures, two more than last year. David Ford, head of achievement services at Durham County Council, said Ofsted had judged both schools to have made significant improvements since the classification.