Teachers are warning that there is strong support for a boycott of tests in schools for children up to the age of 14.
A survey by the National Union of Teachers found that testing placed 'unnecessary stress' and burden on both pupils and teachers.
In primary schools, 93.1 per cent of teachers and 85 per cent of secondary teachers said the tests were stressful for pupils.
Doug McAvoy, General Secretary of the NUT commented: 'This survey underlines the strong criticisms teachers have of these tests. The Government would be hard put to find a teacher who thinks they are beneficial, improve achievement, or promote a broad and balanced education for our children.'
Some 90 per cent of teachers felt the tests diminished pupils' access to a broad and balanced curriculum and this view was found to be strongest among primary teachers at 93.1 per cent compared with 84.3 per cent of secondary teachers.
The NUT's survey found that only 6 per cent of teachers believed that the tests were a reliable method of evaluating pupil achievement and more than three-quarters said they did not help teachers diagnose pupils' learning needs.
Mr McAvoy issued a strong warning to the Government about ignoring the strength of support for a boycott of the tests in November.
The survey found that support was strongest for a ballot to boycott Key Stage 1 tests at 82.5 per cent of teachers, 71.4 per cent supported a boycott of Key Stage 2 and 64 per cent were in favour of action for Key Stage 3.
Mr McAvoy stated: 'The Union's national executive will study this report, including the overwhelming support for a boycott, when it meets in early November. The Government must not continue to ignore the strength of professional opinion based on many years of dealing with these tests.'
The union wants the Government to abandon the tests and replace them with teachers' assessment of pupils.
Mr McAvoy added: 'The strength of Union members' views is undoubtedly replicated across the profession. The Government should end the tests and free teachers to use teacher assessment to determine pupils needs and inform parents of pupil progress.'
The union wants the Government to follow the lead of Scotland and Wales and put a review in of the testing system.