THE number of schools judged to be failing and requiring "special measures" is on the increase, according to education watchdog Ofsted.

By the end of the last spring term, 15 schools in the North-East and North Yorkshire were placed in the inspectorate's lowest category.

This compared to 12 in special measures during the same period last year.

Last night, Nick Seaton, the York-based chairman of the Campaign for Real Education, a pressure group which campaigns for higher standards and more choice in state education, said he was concerned that not enough was being done to improve some failing schools.

He said: "If more schools are being placed in special measures then that is very serious indeed for the children involved.

"Some schools are taking far too long to turn around and that is the responsibility of the headteachers and the school governors, along with the Local Education Authorities, who should be putting in place effective changes to improve the situation."

Schools listed as being in special measures include the Pupil Referral Unit (PRU), in Darlington, which last December received the worst Ofsted report the town had ever seen.

The PRU takes pupils that have been excluded from the town's secondary schools and is to move from its base in McMullen House, Yarm Road, to the former Rise Carr Primary School buildings, in Eldon Street, Darlington, next year, as part of a £2m revamp.

A spokesman for Darlington Borough Council said: "There is a robust action plan in place to raise standards at the Pupil Referral Unit and the council is committed to achieving this goal.

"There has already been one monitoring visit from Ofsted since it went into special measures.

"There would need to be a second visit and a formal re-inspection before it could be considered for coming out of the category."

Of the 15 schools listed by Ofsted, the Unity City Academy, in Middlesbrough, was removed from special measures as recently as last week after an inspection showed the standard of teaching and learning had improved significantly.

The school, which opened in 2002, had been in special measures for two years, with inspectors complaining of truancy problems, poor teaching and exceptionally low exam results.

Across England, Ofsted said that by the end of the spring term, on March 31, 256 schools were in special measures.

This represented a five per cent increase in three months, from the 243 schools in special measures at the end of December last year.

Schools in special measures are judged to be failing to give their pupils an acceptable standard of education.

They face being closed down if they do not improve quickly enough.

Schools Minister Jim Knight said the number of failing schools had halved since 1997 - from 515 to 256.

He said a new tougher inspection framework meant there was no room for what he called "coasting schools".