The number of schools failing an inspection has plummeted to a six-year low.
Figures which confirm the big drop in schools in special measures, first revealed in The TES in July, show that 139 primary, secondary and special schools and pupil-referral units failed inspections, during the past academic year, down 40 per cent on the previous year's total of 231.
In the second-worst category - serious weaknesses - numbers also fell dramatically from 316 to 193.
Teacher unions said the figures undermined the Government's White Paper proposal to force all local authorities to consider bringing in private firms every time a school fails or is found to have serious weaknesses.
John Chowcat, general secretary of the National Association of Educational Inspectors, Advisers and Consultants, said: "There's no doubt that this reflects improvements at school level. But it reflects also the improving performance of a number of local authorities, in particular in concentrating on schools which are in danger of slipping into special measures or serious weaknesses."
A spokeswoman for the Office for Standards in Education urged caution. She pointed out that inspections were moving towards the end of a six-year cycle begun in 1997. Schools known to be struggling were often inspected first.
The number of inspections is also lower than it was in the mid-1990s when most schools were inspected every four years instead of the current six.