The headteacher of an Oxford school, whose pupils consist of 41 different nationalities, has hit out at a grading system which ranked it the worst in Oxfordshire.

Of the 1,049 children at Oxford Community School (OCS), in Glanville Road, just 665 have English as a first language, while a recent newsletter to parents needed to be translated into five other languages - Portuguese, Polish, Albanian, Punjabi and Bengali.

Headteacher Steve Lunt said these facts were an important context for the school's results in Key Stage Three exams, published in the Oxford Mail last week. They ranked OCS bottom out of 33 state secondary schools in the county on raw, non-value-added data.

The table recorded the percentage of pupils aged 14 achieving Level Five - the level expected of pupils at that age - or above in English, maths and science.

Mr Lunt said the raw statistics were misleading, and that if you looked at the value added scores, the school would be ranked seventh out of 33.

Value-added scores are intended to show the level of progress students make since they were previously tested at Key Stage Two.

"That's a really important point," he said.

"Parents often say they want their children to make good progress, regardless of their ability.

"They say they want their child to do their best and valued-added scores are a method for judging progress.

"League tables do include them, but it is rarely rank-ordered for comparative purposes, even though it is a better indicator of the quality of a school's work, as raw percentages merely indicate the profile of the student body.

"Of course, value-added scores aren't perfect either. For example, children from very disadvantaged backgrounds may struggle to engage with a school at all."

Mr Lunt added: "Rather than becoming obsessed with data let's also consider that a good school needs three things - good leadership, quality teaching, and a balanced academic intake who are all making progress."

For 22 per cent of students at OCS, English is studied as an additional language, while 25 per cent have special educational needs.

Mr Lunt said that some of the school's best students did not have English as a first language, but admitted language barriers were an undoubted obstacle to swifter progress for many.

Matthew Arnold School, in Oxford, came top in the Key Stage Three exams - sat in May - in both the aggregate and value-added scores.