The Department for Education has acknowledged that the proportion of schools rated "good" or "outstanding" by Ofsted has fallen over the past two years.
The admission comes as ministers continue to use a different statistic to paint a rosier picture of trends in outcomes of school Ofsted inspection, despite criticism from the government's statistics watchdog.
Earlier this month, schools minister Nick Gibb repeated that there are “1.9 million more children attending 'good' or 'outstanding' schools compared to 2010”.
Background: Ofsted keeping four inspection grades
In October, the UK Statistics Authority warned that by using this statistic the DfE did “not give a full picture”. They said it "should be set in the context of increasing pupil numbers, changes to the inspection framework and some inspections that are now long in the past”.
Now a DfE document setting out Damian Hinds' key priorities acknowledges a downward trend in school Ofsted outcomes since August 2017.
The Single Departmental Plan published today shows that the percentage of schools rated at least "good" peaked at 87 per cent in August 2017, before falling to 86 per cent one year later, and 85 per cent by December 2018.
It says the way the department reports on inspection outcomes is "now more comprehensive and transparent".
The plan lists “maintain our focus on ensuring all children can access a place at a ‘good’ or ‘outstanding’ school” as one of the DfE's priorities.
A DfE press release issued ahead of the plan’s publication highlighted “the positive progress made by the Department for Education since the publication of its previous plan”, which was issued in May 2018.
It cited as evidence a rise in the number of council children’s services departments rated "good" or "outstanding" by Ofsted, but did not mention the fall in the proportion of schools with the same grades.
Today’s plan adds a new DfE priority about children with SEND, who were not explicitly mentioned in the previous version of the plan.
The DfE’s updated priorities for children’s services, early years and wellbeing lists “working with health partners to deliver high-quality services for children and young people with special educational needs and disability”.
The document highlights a rise in the proportion of pupils achieving a grade 5 or above in English and maths GCSEs in state-funded schools, from 42.6 per cent in 2017 to 43.3 per cent in 2018.
It also cites a slight improvement in the DfE’s index measuring the attainment gap between disadvantaged pupils and their peers at key stage 2 over the same period, and a slight worsening at key stage 4.
The plan also adds a fifth item to its list of the DfE’s main delivery areas: “EU Exit”.