Further details of how primary pupils around England fared in their Sats tests this summer will be published on Thursday.
Nationally, 53 per cent of ten and 11-year-olds reached the new expected standard in reading, writing and maths.
On Thursday, the government will publish data showing the differences in performance between the regions and between local authorities.
Individual school results are due to be published in December.
This year was the first year of the new Sats, and the “chaos and confusion” surrounding their introduction has prompted unions to warn they are considering a boycott of the 2017 tests unless significant changes are made.
One of the key concerns of the NAHT headteachers’ union is that moderation of writing, which is teacher assessed, has varied widely between local authorities.
Nationally, 66 per cent of pupils achieved the expected standard in reading but 74 per cent of pupils achieved the expected standard in writing.
I fear there are many schools suffering as a result of inconsistent writing moderation...what a shambles! https://t.co/B3ycB2gaiD— Primary Teacher (@CoreLead_KS2) 5 July 2016
That Writing has come out as highest national figure at KS2 tells you everything you need to know about this year's KS2 cock-ups!— Michael Tidd (@MichaelT1979) 5 July 2016
The Department for Education has said that if its guidance is followed the moderation of writing will be consistent. It has pointed out that the Standards and Testing Agency moderates 25 per cent of all local authorities to ensure they are following the guidance.
Schools will also be able to access their progress data through a secure website, which will show how many of their pupils have made the expected progress. This will be calculated by looking at how pupils have done when compared with pupils who had the same attainment at age 7. The progress data is not expected to be published on Thursday, but will be published in December.