FARTOWN High School is back in special measures.
The school has been returned to special measures after inspectors found it was still failing in key areas.
Schools inspectorate Ofsted found Fartown High School was "failing to give its pupils an acceptable standard of education" following an October visit to check on its progress.
The school, which has 500 pupils, was taken off special measures 18 months ago after inspectors decided they were no longer necessary.
But in its latest report published last week the regulator found national test results for 14-year-olds in English, maths and science had fallen by 10% and were 20% below the school's target.
The number of GCSE students attaining grades A* to C had also dropped by 9% to only 27%.
In anticipation of the special measures decision, acting head teacher Steve Britton and Spen Valley High head Angela Cross, Fartown's executive head, were appointed.
Inspectors reported learning in two fifths of lessons to be "unsatisfactory" or "poor" and found teaching in a third of all lessons to be below standard.
Mr Britton was praised for quickly identifying the school's strengths and weaknesses in the short time he had been in post since September 2004.
And inspectors were satisfied that with the support of Ms Cross, a clear direction for the school was being provided.
But the report concluded special measures were required to address the unacceptable standard of education being provided.
Mr Britton said: "The school and governing body agreed with the recommendations made, which were already part of the action plan."