The acting principal of a Sutton secondary school said he is 'committed to making the school the best it can be' after it was judged to be inadequate by Ofsted.
The education watchdog produced a report into Sutton Community Academy following an inspection, which states that safeguarding is a "considerable weaknesses".
The report states: "Leaders cannot be certain that all staff are suitable to work with children, because they have not carried out all the necessary checks.
"Some leaders were aware that appropriate checks were not being carried out and proceeded to appoint staff nonetheless. Recently, when these failings have been identified, leaders have not assessed potential risks.
Ofsted rated the school, which has 668 pupils, 'inadequate' overall, meaning it is 'performing significantly less well than it might in all the circumstances reasonably be expected to perform.'
Out of five categories, the school was judged to be inadequate in two, and require improvement in three.
The report stated: "Trust and school leaders have not fulfilled their statutory duties to ensure that safeguarding arrangements are effective.
"Leaders have not identified potential risks quickly enough, or taken adequate action to reduce them.
The school has also been ordered to "reduce the proportion of disadvantaged pupils who are persistently absent from school."
The report adds: "Parents’ views about the school are mixed. Many parents are positive about the school. However, of those parents who responded to Parent View, Ofsted’s online questionnaire, a significant number said that they did not feel that the school responded well to their concerns."
The last inspection in 2016 deemed the school to be 'good'
Inspectors say that the school must now "urgently address the weaknesses in safeguarding arrangements by ensuring that risk assessments for vulnerable pupils are sufficiently detailed and consider all potential risks".
Acting principal David Mackey, who was appointed principal in March, said the rating is 'frustrating'.
In a letter to parents, he said: "You will be aware that I had been in post for four weeks prior to the inspection and I can assure you that any and all historical safeguarding issues were alleviated prior to this inspection, or have been remedied with immediate effect.
"I am committed to making the academy the best it can be.
"It is particularly frustrating that despite Ofsted judging the behaviour of pupils as 'requiring improvement', this does not represent how pupils conduct themselves well around school and in lessons.
"Visitors to our academy frequently comment on the positive atmosphere around the site, and the positive relationships between staff and pupils."
Sutton Community Academy, on High Pavement, was praised by inspectors, for supporting pupils with special educational needs and/or disabilities.
Pupils were also commended for their conduct, and for being 'polite, confident and happy'.
A spokesman from the school said: "The limiting judgement related to safeguarding meant that other judgements such as leadership and management, and personal development, behaviour and welfare were lower than we absolutely believe them to be."
“We are passionately committed to getting things right for the academy, its talented students and our local community.
"Under an excellent new Principal, we are very confident that this will be the case and we are hopeful of achieving record exam results this summer.
“We had already drawn up, and were implementing, an action plan to address the areas we need to improve; these actions will ensure sustained progress.
"They are having a positive impact, with better attendance, improvements in teaching and a robust new safeguarding procedure already happening.
"We also established a new parent steering group (PSG) during the Autumn term, so that we can listen more effectively to our families and our community.”
“We all want to achieve higher standards across all aspects of academy life, and we are grateful for the support of the whole academy community as we work towards this.”