Test marks queried by one in 7 primaries
The figures disclose the lack of faith teachers have in the system on which the national targets depend and come just a month after more than a million children sat this year's tests.
Last year 2,210 of the 16,364 schools that sat key stage 2 English tests returned papers for a marking review. Almost 4,000 11-year-olds had English results upgraded.
One in 45 markers of primary English tests were sacked last year after their marking was found to be unreliable, official figures also reveal.
Martin Tibbetts, chair of the National Association for the Teaching of English, said: "This demonstrates how little confidence teachers have in the testing system.
"Teachers get the scripts back and can see for themselves that the marking is unreliable. Ministers should trust teachers' judgments and rely on teacher assessments rather than tests - they are happy to do this at key stage 1, so why not for key stage 2?"
Last year 629,000 English scripts written by 11-year-olds were graded by 2,045 markers. But 45 markers were judged to be marking inaccurately and were dismissed.
The primary English test provokes by far the most complaints about marking, and markers of its papers were far more likely to be dismissed than other examiners.
Only five primary maths and four primary science markers were dismissed out of 1,600 for each subject.
Meanwhile, a study by the Office for Standards in Education this week concluded that Government literacy targets for 11year-olds would not be met unless children's writing improved significantly in the next two years.
Primaries are paying insufficient attention to writing within the national literacy strategy. Where it is taught, too many lessons display weaknesses, OFSTED concluded.
The study of 300 literacy hours found that in some cases, writing tuition amounted to students just being asked to copy lists of adjectives, or to write out vocabulary definitions from a dictionary.
Overall, teaching of writing was found to be unsatisfactory in one quarter of lessons visited.
Michael Fullan, the Canadian academic evaluating the literacy and numeracy strategies, said ministers had to continue high levels of spending if they wanted to sustain improvement.
Professor Fullan said the national strategies had led to early gains, but the pound;100 million being spent annually needed to be maintained beyond the next general election.
"There has been a very impressive improvement in standards, but it is not deep-rooted and could be fairly fragile," he said. "Tests results are not everything, but they are a strong indicator."
National tests are taken by all 11 and 14-year-olds in English, maths and science and by seven-year-olds in English and maths. Infants' tests are marked by their own teachers but all other national tests are graded by around 10,000 external markers - usually serving teachers, heads and education advisers. They work for exam boards which mark the tests under contract to the Government's testing quango, the Qualifications and Curriculum Authority.