A “SERIOUS incident” is under investigation at a school for autistic children, which has been graded as “inadequate” by Ofsted after concerns were raised over the safety of some pupils.

Inspectors visited Tadley Court in November and a report on the education and residential provision, published in December, said: “The daily supervision of a very few students is not good enough to secure their safety.”

However, the school has said it will be making a “robust complaint” to Ofsted about aspects of the report.

The school, formerly known as Tadley Horizon, was previously visited by the education watchdog last February, after which a social care inspection report graded the institution as “inadequate” having found that children were put in illegal “cell-type” rooms as a form of restraint.

The independent school, in Tadley Common Road, is a residential special school providing care and education for 54 young people aged five to 19 who have autistic spectrum disorders. Twenty-seven of the students are residential.

The previous report said ‘calm rooms’ were illegally used to restrict the liberty of residential pupils, and that their use was “excessive”.

A spokesman for the school told The Gazette at the time that it was challenging the “factual accuracy of some aspects of this report” but would “undertake a thorough review of our policies and procedures for behavioural management.”

Inspectors visiting in November reported that the school is “inadequate” overall, although several areas were graded as “good”. These were pupils’ achievement and behaviour, the quality of teaching and the curriculum.

The leadership and management and overall effectiveness of the residential experience were both graded as “inadequate.”

The school is managed by The Priory Education Services, which is part of The Priory Group.

The report said: “The proprietors and senior leaders have not ensured sufficient improvement in the residential provision since the last inspection.” It added: “The school does not meet the national minimum standards for residential special schools.”

Inspectors said students achieve well and their behaviour and personal development are good. They reported: “The school and boarding houses are generally calm and purposeful. Students respond well to the good teaching and engage positively in lessons and activities in the residential home.”

However, the report added: “Some safeguarding risk assessments, such as levels of supervision, have not been modified in the light of students leaving the premises without permission. These have put a very few of the residential students at considerable risk.”

Since the last inspection, the report said there had be a full review of the use of physical intervention and restrictive practices.

It added: “This has led to comprehensive changes and substantial improvements in the approach to behaviour management.”

The leadership and management was graded “inadequate” because of the failings to keep all students safe. However, the report said that a new headteacher has “strengthened the quality of teaching and the curriculum.”

The report noted that a “serious incident”, which happened since the previous inspection, was under investigation by the authorities.

It added: “Actions taken by the setting in response to the incident were considered alongside the other evidence available at the time of the inspection to inform inspectors’ judgements.”

Caroline Walker, a spokeswoman for the school, said it does not want to comment on the details of the report until the “robust complaint” has been resolved.

She added: “However, we are committed to providing the very highest standards of education and care for pupils and are confident that the school is a safe environment. We always welcome constructive feedback and are dedicated to continually improving the school.”