Almost a thousand primary schools are failing to give their pupils a decent grounding in reading, writing and arithmetic, official figures suggest.
Newly published data shows that 962 primaries in England would be classed as failing under tough new targets announced by the Government last month.
The statistic comes in new primary school league tables, which also highlight the chaos caused by this year's boycott of national curriculum, or Sats, tests.
The new target, published in an education White Paper, said primaries will fall below the bar if fewer than 60% of their pupils reach Level 4 - the standard expected of the age group - in English and maths and fewer youngsters make two levels of progress in the subjects than the national average.
According to the latest figures, the national average for English this year was 87% making two levels of progress and for maths it was 86%. Those that fail to reach the target face closure or being taken over.
The primary school league tables show that 962 schools, out of around 11,500 for whom results are known, fail to meet this threshold. This figure will have been affected by the boycott. Last year, 1,631 schools would have fallen below, the Department for Education said.
The target was introduced as part of a major overhaul of England's schools system, and Schools Minister Nick Gibb insisted the new standards were "firm but fair".
He said the statistics show that many primaries are providing a "first-class education." But he added: "Currently half of all 10 and 11-year-old boys who qualify for free school meals are being let down by our education system. It is unacceptable that after seven years of primary school these children are not at the standard in English and maths that they need to flourish at secondary school."
The primary school league tables show how every 11-year-old in England performed in English and maths tests. Data for a quarter of schools, around 4,000 in total, is missing due to a boycott by two teaching unions, the National Union of Teachers (NUT) and the National Association of Headteachers (NAHT).
The tables reveal that slightly more primaries scored full marks than last year. They suggest that 289 primaries succeeded in making sure every 11-year-old left with Level 4 in both English and maths, compared to 282 last year.