The Government wasted pound;13 million on this year's national curriculum tests for 14-year-olds which have little educational value and are potentially harmful to pupils, according to a study by the Association of Teachers and Lecturers.
Pressure to achieve good results has undermined the breadth and balance of the curriculum as most teachers feel increasingly obliged to teach to the tests, the study found.
Last month, The TES revealed that Chris Woodhead, the Government's chief inspector of schools, believes that the current national curriculum tests are unreliable.
Mr Woodhead told a public seminar at the London School of Economics that the tests were vague, unreliable and administered creatively by schools to get good results.
Peter Smith, general secretary of the ATL, claimed the new evidence confirmed Mr Woodhead's concerns and called for an urgent review of the tests.
The association, the third-largest teaching union in England and Wales, conducted the survey in partnership with the National Association for the Teaching of English and the Association of Teachers of Mathematics.
They concluded: "The purposes to which national test results are now being put is profoundly de-professionalising, subverting good practice in assessment and, consequently, in the process of teaching and learning. The ultimate losers are the pupils.
"We must continue to question the educational value of these high-cost, high-stakes tests. Seven years on since the introduction of statutory assessment at key stage 3, where is the evidence that national tests are genuinely raising standards?" Ministers set great store by the test results and have encouraged parents to use them to judge school performance.
David Blunkett, the Education and Employment Secretary, had planned to publish grades for every secondary school this year according to improvement shown by pupils between national tests at 14 and GCSE at 16. He dropped the proposal at the last minute after protests from schools.
Mr Smith said: "The Qualifications and Curriculum Authority must as a matter of urgency review the way tests are both set and marked.
"When teachers and the Government's chief inspector join in a chorus of concern, something must be badly wrong."
The survey of 550 teachers revealed serious concerns about the reliability of the tests and the quality of external marking, particularly in English.
Some 90 per cent of English teachers said they felt under pressure to teach to the tests although 67 per cent said they were not a valid assessment of the key stage 3 programme of study.
Fewer than 10 per cent of responses offered any kind of positive comment. A substantial minority added critical comments to their questionnaire, describing the tests as "a farce", "a waste of time", "pointless" and "alarming".
Others described the marking and administration as "frightening", "appalling", "disgraceful" and "a disaster".
In maths, only 27 per cent of teachers agreed that the tests reflected good mathematics teaching while nearly three in five said they were under pressure to teach to the tests.