Rothwell’s Montsaye Academy has been told it must rapidly improve after being given the lowest possible rating by education inspectors.
The school in Greening Road has been heavily criticised in a number of areas by the watchdog Ofsted.
It currently caters for 1,061 pupils and was rated as ‘good’ in its previous inspection.
But Ofsted now says it has significantly declined and has resulted in poor outcomes for pupils at Key Stage 4.
The report said: “Key aspects of the school’s performance have declined significantly since the last inspection, with the result that outcomes for pupils by the end of Key Stage 4 are inadequate.
“In the past two years, pupils’ achievement has been inadequate in mathematics, science, modern foreign languages and humanities.
“The quality of teaching is inadequate.
“Pupils experience far too much inconsistency in the teaching they receive.
“Strategies to improve the quality of teaching across the school have not been effective enough.”
The school appointed Colin Boxall as interim headteacher last month after the sudden departure of Jason Cumming as headteacher just before Christmas.
The report also branded the leadership and management at the time of the inspection – November 30/December 1 – as inadequate.
It said: “Since the previous inspection, key aspects of the school’s performance have declined significantly.
“Leaders and managers have proved to be ineffective in arresting this decline and bringing about the rapid improvements needed.
“Senior staff have failed to ensure that their good intentions and high aspirations for pupils are reflected in the day-to-day teaching and the behaviour the pupils experience.
“The school’s arrangements for the performance management of staff have proved to be ineffective in securing the improvements needed.
“The link between the pay increases awarded to teachers and the performance of their examination classes is not strong enough.”
However, the school did receive praise for the improvement in achievement in English and for effective safeguarding.
Montsaye has been contacted for a comment.