Test preparation makes primary school a "pressure cooker" for some children, a senior government adviser has told MPs.
Former Ofsted director Jim Rose said it was "a real issue" for some schools.
Mr Rose is chairing the government's review of how children in England learn to read - now also the subject of a Commons education committee inquiry.
He told the committee that "teaching to the test" sensibly was often unavoidable - but taken to extremes it "put children into straitjackets".
Responsibility
"The test is testing things you want children to see gains in," he said.
"Now, if you allow that to become a pressure cooker in your school and press down, down, down to the reception class, people feel they have got to do things which put children into straitjackets and things start to go pear-shaped.
"That's wrong."
Asked how widespread the problem was, he said: "It's difficult to say but we should be registering that as a real issue."
He said that was not necessarily a criticism of testing, but of how it was conducted.
"Once you accept that we need tests - and we do - then there is a professional responsibility that we see they are handled properly."
Targets
There is a concern among many teachers - reflected by their unions - that they are obliged to "teach to the test", not least because of the pressure of league tables.
The government sets targets, which percolate down through the system to each school, for the attainment of children at certain stages in their schooling.
The high-profile Key Stage 2 national curriculum tests, taken when children are in the final year of primary school at the age of 10 or 11, assess their attainment in English, maths and science.
Last year there was a rise of one percentage point to 79% of pupils reaching the expected standard in English and 75% in maths.
The government target is that 85% will make the grade in English and maths by 2006.
Previous relatively large gains have been disputed.
The official Statistics Commission said ministers "substantially overstated" the improvements in primary school standards between 1995 and 2000 by relying on test results as proof.
But the Department for Education disputed the findings of its own research on the subject and says primary school standards have seen "dramatic and sustained" improvements.
^ Back to top | BBC Sport Home | BBC Homepage | Contact us | Help | ©