A secondary school which became an academy last year “requires improvements”, Ofsted inspectors said.

Following a visit to The Beaconsfield School, in Wattleton Road, both the behaviour and achievement of students appear to be falling behind, while the quality of teaching was also said to need improving.

It was the first time Ofsted has inspected the school since they switched to academy status in March 2013 and headteacher John Fletcher said they will be lodging a formal challenge against the decision.

In a letter home to parents, he said: “There are elements which we feel do not truly represent the school and are therefore challenging the overall grading of a three [requires improvements].

“We are in the process of lodging a formal challenge to the report with Ofsted.

“The basis of this challenge is that our students make better progress given their ability on entry to the school then others do nationally.

“We are aware of a number of schools that have been given a grade two [good] overall despite their students making less progress than ours given the same starting points.

“In the meantime while we are waiting for the outcome of the challenge if you have any questions please do not hesitate to contact us.”

In the report, which was conducted over two days in October, the leadership and management as well as sixth form provisions at the school were both found to be “good”.

However, the inspectors found the quality of teaching was not yet up to the same level.

The report said: “The quality of teaching is improving, but is still too variable to be good. Some teachers’ planning places insufficient focus on ensuring the work set for higher and middle attaining students is challenging enough.”

They added: “Marking is inconsistent. Some teachers do not mark work frequently enough or give specific guidance to help students improve.

“[And] students’ behaviour is not yet good because it differs too much between subjects and groups.”

However, the Ofsted report did pick out a number of strengths the school had and once again highlighted the efforts of Mr Fletcher.

The report said: “The headteacher has single-mindedly moved the school forward. Staffing issues have been resolved... and the majority of parents support the school.”

Earlier this year the school celebrated the third year of increasing GCSE results with 62 per cent of students achieving five or more A* to C grades including English and maths.

In total the English department achieved 81 per cent A*to C of which 48 per cent were A*to B grades and 33 per cent of students within the maths department celebrated achieving an A*to B grade.