Leaders of a Northampton all-through school have been scolded for having a "generous" opinion of their own teaching quality after slipping up in a recent inspection.
Ofsted has rated Caroline Chisholm School, in Wootton Fields, as "requires improvement" in nearly every field, down from a "good" grade in their last rating.
The watchdog criticised the school's leaders for dropping the "high standards" found in their last visit in 2012 and has ordered them to improve.
Principal David James has called the result a "disappointment" in a letter sent home to parents today (November 22).
The Ofsted inspection, published on November 21, reads: "For too long, leaders’ view of the quality of the school’s provision has been too generous.
"This is because they have focused on pupils’ attainment, which has been high, rather than on the progress that pupils make, which has been average.
"The quality of teaching is not of a high enough level across the school to ensure that pupils make good progress.
"Since joining the school, the principal has ensured that all leaders have a more accurate view of the quality of the school’s provision."
However, the school's early years provision for pupils heading into Year 1 is now rated "outstanding", with inspectors praising the "very strong" leadership. Every other area in the school has been rated worse.
Ofsted has ordered the school to improve the quality of their leadership, teaching and revisit how they use the pupil premium funding.
In a letter home to parents, principal David James, who took up the post in 2015, said there had not been enough "progress" to maintain the school historic "good" rating.
He wrote: "The inspection team, however, have given us clear areas that we need to focus on for us to
move rapidly back to Good.
"The school leadership and the teaching staff are determined to use the inspection findings as a catalyst to accelerate the rate of improvement in the school."
Caroline Chisholm GCSE grades from 2017 improved on 2016, where over half of all grades were between A* and B. The Key Stage 1 pupils also placed in the top eight-per-cent in England in a recent phonics test.