Failings in care for sick children have led a previously outstanding nursery to be rated inadequate by inspectors.

Hall Farm Nursery School in Hargham, near Attleborough, had held Ofsted's top grading since its first inspection in 2011 before being given its lowest ranking following an inspection earlier this month.

While the quality of teaching and outcomes for children were still judged to be good, children's development, behaviour and welfare and the effectiveness of management were rated inadequate.

The nursery said the drop in grade was the result of an isolated incident.

Ofsted said the assessment was carried out in response to information it received about the nursery.

After their visit on July 4, inspectors said staff were jeopardising children's health and safety by not consistently following procedures for dealing with children who became ill.

They said managers had failed to identify weaknesses in the nursery's safeguarding practises and that children's safety and welfare were "not fully assured".

But their report said management had a clear action plan in place and regularly monitored the nursery to identify areas for improvement.

Staff were said to help children feel safe and secure at the nursery, were aware of children's dietary needs and allergies and carried out daily checks on the premises.

On teaching and learning, inspectors said staff knew children's interests and provided them with "stimulating learning environments".

Children were said to make good progress in readiness for starting school, both in their personal and educational development, and parents spoke highly of the nursery and staff.

Gayle Mitchell, nursery manager, said: "The management and staff are devastated that an isolated incident has resulted in the nursery being rated grade four [inadeqaute].

"The nursery is working closely with Norfolk County Council and Ofsted and expects to be re-inspected within three to six months."

According to Ofsted the nursery has 189 children on its roll and employs 37 members of childcare staff.

Back in January the nursery attracted criticism after saying that parents who didn't pay an optional surcharge could see their children put in a separate class. The nursery claimed the implementation of the surcharge was in line with government guidance.