This week, the Commons education and skills select committee and Sir Al Aynsley Green, the children's commissioner, became the latest to question the relentless focus on testing.
Christine Gilbert, the chief inspector, has also called for an investigation into the effects of the current testing regime.
Concerns centre on the narrowing effect on the curriculum and the impact of pupils being drilled to pass the next test.
The Liberal Democrats said the national tests, backed by league tables, were "perverting education", but the Conservatives said they were the basis of school accountability and had to stay, a position ministers share.
This week, Ken Boston, head of the Qualifications and Curriculum Authority, was reported to have called for the testing regime to be scrapped after proposing a new system of "sample tests".
Instead of the end-of-key stage tests, 3 per cent of pupils would sit new assessments that would be used to judge the Government's education performance. But Dr Boston said schools would still be held to account in league tables through new progress tests, which pupils could sit when teachers believe children are ready.
As the Government announced in January, these are to be piloted in 10 local authorities from September and could be rolled out within three years. Dr Boston's plans mean schools would still face national tests, but pupils would no longer all sit them on the same day.
Testing a sample of pupils to judge national standards would mean papers could be kept from year to year, he said, enabling more reliable comparisons to be made between pupils' performance in different years.
The Government said it has no plans to trial sample tests. It says its new system of progress tests is the way forward for assessment. But The TES understands that testing experts are not convinced. A recent meeting at the Qualifications and Curriculum Authority to discuss the validity of the tests revealed concerns that the move would lead to over-testing.
Dr Gordon Stobart, of London university's Institute of Education, said the new progress tests raised the "awful prospect" of teaching to the test throughout KS2 and 3.
On Tuesday, the Commons education and skills select committee launched a six-month probe into assessment. Barry Sheerman, its chairman, said there were wide concerns it was not working well. He said: "When the whole education community starts speaking very strongly about needing an evolution in the current testing and assessment regime, we have to investigate."
The National Association of Head Teachers also began its own investigation into testing and league tables. Sue Palmer, TES columnist and author of Toxic Childhood, told the inquiry that the pressure on pupils over tests was "criminal" and improving results was crucial to ministerial careers.
She said: "I find it difficult to forgive the politicians for what they have done to our profession, but I will never forgive them for what they are doing to children."
Dr Boston said this week that the current testing regime narrowed teaching but that his proposals would not address this issue.
On Wednesday, the GTC renewed a call first made last year for a national sample test to replace end-of-key-stage assessments. Judy Moorhouse, its chair, said the testing regime was "overloading and distorting". "The time is ripe for change and the profession is hungry for it," she said.
Mary Crowley, chief executive of Parenting UK, is supporting the GTC. She said: "Most parents want their children to be happy, and they don't want them to be subject to unnecessary anxiety."
EIGHT TIMES A YEAR IS TOO MUCH, SAY EXPERTS
The QCA says secondary history and geography staff are being forced to over-test pupils to report back on their progress in minute detail. Most schools use tests to give pupils a national curriculum level in these subjects at least twice a year.
The Historical Association says some pupils are being tested up to eight times a year to inform inspectors, local authorities and parents about pupil progress.
A QCA report on modern languages found most secondaries received no data from primaries about how much teaching their incoming pupils had already had in the subject.
A Department for Education and Skills spokesman said: "The Government's policy is to retain externally marked tests for every pupil. This provides public accountability for schools which has been vital in our success in driving up school standards so sharply over the past decade."