Teachers have been asked to give more feedback on pupils

It reveals that the number of schools deemed below standard in England rose 24% to 160 in 2002-3, the Times Educational Supplement reports.

There were 99 primary schools, 35 secondary, 18 special and eight pupil referral units.

The report comes after the National Association of Head Teachers (NAHT) criticised Ofsted for being "excessively negative" in inspections.

Formal protests

Ofsted brought in a regime in September which was intended to take more account of teachers' views of pupils.

But the NAHT said dissatisfaction was running at "a high level".

Of 31 members who responded to its survey, six had lodged formal protests against inspection reports.

Meanwhile, 10 said their inspection gave grounds for complaint.

The NAHT said some schools were being branded under-achievers even though inspectors judged most lessons "satisfactory".

Last year, Ofsted chief inspector David Bell angered teaching unions when he questioned whether this level of attainment was still adequate.

In a letter to Mr Bell, NAHT general secretary David Hart said: "There is a widespread feeling that it is harder to achieve satisfactory outcomes under the new framework than was the case previously."

An Ofsted spokeswoman said the new inepsctions framework had not caused the rise in failures.

She added: "Given that Ofsted has inspected 1,669 schools over the last term, it is difficult to draw firm conclusions from a survey of just 31 schools, particularly when around half of them expressed satisfaction with Ofsted's inspection process."

The spokeswoman also said: "The new inspection framework was introduced following extensive consultation with head teachers and schools.

"The criteria for judging the effectiveness of both teaching, and leadership and management, have been made clearer in Ofsted's new framework.