Two top Birmingham girls’ schools have been seen their Ofsted ratings downgraded from outstanding in the wake of “no notice” inspections.

Kings Norton Girls’ School and Hillcrest School in Bartley Green dropped from the top rating down to satisfactory – the second lowest – following visits by the Government watchdog last month.

Kings Norton was one of six schools nationwide to be subject to a new “no notice inspection” – meaning that staff were only told the day before to expect a visit.

The inspections follow a stark warning from Ofsted chief Sir Michael Wilshaw earlier this year that schools which did not have outstanding teaching could face being stripped of their top rating.

Both schools now face a repeat inspection within the next two years.

Union bosses said they were “concerned” at the downgrades, accusing Ofsted of “continually moving the goalposts”.

Kings Norton Girls’ School had been awarded outstanding status following an inspection in November 2007.

Inspectors who visited the school on May 10-11 changed the rating to satisfactory, saying teaching was “not good enough” to ensure students made good progress and achievement.

Head teacher Gill Fox said inspectors did “not see a typical week” at the school during the inspection, with internal exams taking place and Year 11 students leaving on the last day of the inspection.

Mrs Fox said: “I think it gave us plenty of food for thought in terms of taking the school forward, and I think overall it was relatively fair.

“It was harsh in some areas using the new criteria, which is a lot higher in terms of the bar that has been set and we have been judged against that.

“Whether it is fair or not, these are the new standards and the bar has been raised and we will move on from this.”

Ofsted ranked leadership and management, behaviour and safety of people and quality of teaching as satisfactory. Inspectors also noted that GCSE results had dipped slightly at the school in 2010, but Mrs Fox said 32 per cent of all GCSE grades were A*-A in 2011.

She added that the school was on course for “record exam results” this summer.

Mrs Fox said: “The results did dip in one or two subjects, but this is not a trend and this year we are set to get some of the best results we have ever had.

“The dip was sandwiched between two very successful years, but they were still broadly average compared to the national average.”

Hillcrest School had previously been judged as outstanding in an inspection in January 2009.

Inspectors who gave the 600-pupil school two days’ notice of an inspection, which took place on May 17-18.

Inspectors gave the school an overall rating of satisfactory, but said that the quality of teaching, pupil behaviour and leadership were all “good”. The inspectors said: “This is a satisfactory school, where individuals are valued and nurtured.

“Standards have deteriorated since the last inspection, however this is being addressed by good leadership.”

Wayne Bates, Secretary of Birmingham NASUWT said he was concerned that both schools – who both became academies in 2011 – could not turn to the local authority for help in improving.

He said: “Schools being downgraded by Ofsted is becoming increasingly common across England, not because schools are necessarily doing a poorer job, but because of the continual moving of the goalposts.

“It is a concern, however, that these two schools, having recently chosen academy status, are now divorced from the Local Authority’s support and guidance while attempting to regain their higher ratings, which can only make the task more difficult.

“School improvement is achieved through schools working collaboratively in partnerships under the umbrella of a supportive local authority providing a strategic lead, not through setting schools in competition against each other.”

In spite of repeated calls, Hillcrest School did not make a comment.