OFSTED has ruled the Highcrest Academy “requires improvement”.

But Highcrest – which was ranked “outstanding” in its final inspection as a secondary school in 2010 before it converted to an academy last year – believes the judgement is “unfair”.

Inspectors ruled the proportion of Highcrest pupils obtaining five A* to C grades including English and maths has “not improved rapidly enough” and was below the national average.

They also raised concerns about the performance of the Sixth Form - stating Highcrest needed to improve its retention rates, quality of provision and students’ outcomes by making sure the courses on offer fully meet students’ needs and that teaching is consistently good.

Inspectors said governors are committed and have effective committee systems in place but ‘do not have a clear enough view of the school’s performance which limits their ability ask challenging questions’.

The report does however praise the overall quality of teaching and the behaviour and attitude of the academy’s children.

Ofsted also praised the progress made by students in English, science and maths subjects, as well as the development of disabled pupils and children who use English as an additional language.

The government brought in the new “requires improvement” rating to replace “satisfactory” in a bid to improve standards in schools.

In a letter sent home to parents last week, Chris Turner, Chairman of Governors at Highcrest, said: “There were many encouraging conclusions in the report.

“However, the governors take issue with the main judgement which said the overall effectiveness of the academy ‘requires improvement’.”

He said, under the new rules, inspectors were unable to take into account the “dramatic improvement” of Highcrest over the last decade or the demographic and area it serves in a selective county.

Highcrest was being judged against national standards based on comprehensive schools – yet more than 40 percent of Bucks children attend a grammar school instead of a comprehensive school, he said.

Mr Turner added: “The rating of “requires improvement” for [the] Achievement of Pupils [category] has the knock-on effect of limiting the overall grade and the grade for Leadership and Management which we believe is an unfair reflection of the work of our students, staff and the governing body...

“We do not believe Highcrest has declined in the last three years. In fact, there is strong evidence to the contrary. Make no mistake; this is an academy in very good shape.”

Failing Hatters Lane Upper School was closed by Ofsted in 2001 before it was relaunched as Highcrest Community School under the Labour government’s Fresh Start scheme in 2001.

It received an “outstanding” rating by inspectors in 2010 before it converted into an academy last year.

Highcrest introduced a controversial new admissions test in September 2012, which principal Shena Moynihan said could pose a “real challenge” to the county’s 11+ system.

Lakshan Wanigasooriya, a Labour spokesman in Totteridge, called the academy’s first Ofsted report “disappointing”.

The full Ofsted report can be found by clicking here.