Chickenley Community School has been given the worst rating by Ofsted and will be put in special measures.
Inspectors said the achievement of pupils, quality of teaching, and leadership and management at the school in Princess Road were inadequate, while the behaviour and safety of pupils “requires improvement”.
Standards have slipped at the school, which was deemed satisfactory in an inspection in October 2011.
Inspectors highlighted “weaknesses in the quality of teaching” for pupil underachievement during the inspection in November last year. The report added: “Standards in reading, writing and mathematics are too low. Teachers do not teach the basic skills in these subjects systematically or give pupils enough chance to practise reading, writing and basic mathematical skills.”
The work teachers set is often too easy and they do not set clear boundaries for pupils behaviour, occasionally allowing bad behaviour to disrupt lessons.
The report also criticised the school’s management and leadership, saying they have not demonstrated they have the capacity to secure the necessary improvement in the school.
Teachers are not given enough direction or guidance on how to improve and inspectors said newly qualified teachers should not be employed at the school.
The report did praise the school’s role in the Chickenley Campus and its links with the on-site community centre, as well a significant improvement in attendance over the last year.
Headteacher Bronagh King said the judgment was “very disappointing” but said the school had already identified areas for improvement and was “working to raise standards to a higher, more consistent level”.
She added: “Progress has already been made in key areas. For example, Ofsted noted positive changes in the way pupils learn to read, they reported that new systems are having an impact and they highlighted improvements in behaviour. They also noted the indications of improvement at Key Stage 1.
“Some of our development work will take longer to show its benefits, but we are confident that the school is heading in the right direction.
“Though the overall judgement is very disappointing, Ofsted highlighted several positives including examples of good teaching, the progress of early years children and standards of social, spiritual, moral and cultural learning.”
Chickenley will now receive regular monitoring by Ofsted inspectors.
A council spokesman said: “We will continue to work very closely with the school and provide extra support to the current senior leadership team. “An action plan is in place, along with other measures, so that issues can be addressed and standards can be improved as a matter of urgency.”