SHENFIELD High School has been told to raise its standards or face "special measures".
The latest report by Ofsted said the school in Alexander Lane "requires improvement" and highlighted eight areas in need of attention, including English and maths, under-achievement in GCSEs and A levels, and a "poor quality of marking", sometimes leaving students unsure about how to improve their work.
The assessment, published last week, also echoed concerns of parents, staff and students over the behaviour of a small number of "boisterous" and "defiant" pupils disrupting lessons.
The school received the same grading at its last inspection in 2009, although it was then described as "satisfactory".
The Government introduced "requires improvement" in September this year to clamp down on "coasting" schools.
Head teacher Carole Herman, who joined Shenfield High School last year, said: "This is a tough new Ofsted framework where satisfactory just isn't good enough. It never has been in my view.
"We know what more needs to be done so now it's full steam ahead."
However, the inspectors praised the "good leadership" shown by Mrs Herman since her appointment.
They noted: "She has taken decisive action and implemented a range of systems and initiatives that are beginning to drive and accelerate the improvements in behaviour, the quality of teaching and leadership and management."
As with all level-three schools, Shenfield will be re-inspected within the next two years and will then either be placed in "special measures" or promoted to "good".
