The number of independent schools choosing to enter pupils for key stage 2 Sats has dropped by 25 per cent since the tests were reformed.

Department for Education provisional statistics, published today, show that 253 out of approximately 1,400 eligible independent schools took part in the assessments this summer - a drop of 25 per cent since 2015, when the total stood at 338.

It is compulsory for state-funded schools to administer the Sats at the end of both KS1 and KS2, but independent schools can choose whether to take part or not.

The Sats involve tests in reading, maths and spelling, punctuation and grammar (Spag), and a writing assessment carried out by teachers, which follows nationally set criteria.

The test were reformed in 2016 to match the new “tougher” national curriculum. In their first year, 53 per cent of pupils reached the new expected standard in all of reading, writing and maths; in the previous year, 80 per cent achieved what was then the expected level 4 in the 3Rs.

Since 2016, the proportion of 10- and 11-year-olds reaching the expected standard has risen. This summer, 64 per cent of pupils passed all three subjects.

But the number of independent schools taking part has continued to fall each year since 2015 - with 268 taking part in 2016 and 262 in 2017.

Christopher King, chief executive of the Independent Association of Prep Schools (IAPS), said: “There are a range of reasons why schools have withdrawn from Sats, but I suggest that most IAPS heads would say they believe that withdrawing from Sats had a positive effect on teaching and learning.

“Once freed from the public accountability, teachers relaxed. They still prepared the children, but also created a more appropriate curriculum that was fitted to a more holistic education that’s so characteristic of the best independent schools. 

“Parents are increasingly concerned about the wellbeing of their child and the unnecessary level of stress for no real apparent gain at an early age.

“Parents are very happy to see schools step aside from the Sats whenever they can, and independent schools are in a privileged position where they can do so entirely.”