More schools are failing new-style checks brought in by England's schools' inspectors, it is reported.

The proportion of schools classed as "inadequate" has almost doubled since changes came in last September, says the Times Educational Supplement. Inspection body Ofsted will not comment on the data but says the new checks have focussed on weaker schools. Head teachers are calling for an urgent review of the system and say the bar has been raised too high.

The Times Educational Supplement (TES) has analysed the results of inspections carried out by Ofsted since the changes were brought in. It says only 9.2% of schools have been given the top rating of "outstanding" since then, compared with 19% of those inspected in the academic year of 2008/9.

Ofsted is due to publish a report on the new-style checks next Wednesday and says it cannot comment on the statistics in advance of that.