The latest league tables show how more than 15,000 primary schools performed in national curriculum tests - known as SATs - in English (reading and writing) and maths.
Under the Government's current target, schools are considered failing if fewer than 60% of 11-year-olds reach the expected standard - Level 4 - in English and maths SATs tests, and fewer youngsters make two levels of progress in these subjects than the national average.
The national average for English progress this year is 92%, and for maths it is 90%.
Schools that fail to reach this threshold are at risk of being closed and turned into academies.
The latest figures show that of the 521 schools which are below the bar, 45 have already closed, with 37 becoming academies.
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