The rating, which is the equivalent of an “outstanding” Ofsted grade, was awarded to Pipers Corner School in Pipers Lane following a four-day inspection by the Independent Schools Inspectorate (ISI) in October.
The ISI Inspection examines quality of teaching, pupil achievement, and pastoral care, as well as curricular and extra-curricular provisions.
Headmistress, Mrs Helen Ness-Gifford, said: “We are very pleased to have received such a positive endorsement of our school.