Britain's biggest headteachers' organisation last night delivered a huge snub to the Government and backed a boycott of national curriculum tests for 1.2 million seven- and 11-year-olds.
Members of the National Association of Head Teachers voted for a ballot on boycotting the tests in English, maths and science, despite a plea from the Secretary of State for Schools, Ed Balls, for them to reject the action. Earlier yesterday he described the move as "illegal" and "irresponsible".
The decision, agreed at the association's annual conference in Brighton with 94 per cent of delegates voting for the boycott, is the first time the NAHT has voted on industrial action in its history.
One headteacher, Sue Sayles, a past president of the NAHT, said: "We've got to show Ed we've got balls."
The threat from headteachers is a potentially more serious blow to the tests than a similar decision taken by the National Union of Teachers at its annual conference over the Easter weekend. If the heads refuse to have anything to do with the tests, there is very little chance that they will go ahead.
In his speech to the conference, Mr Balls pleaded with the delegates not to go ahead with the boycott. "I don't think the right thing or responsible thing to do is to boycott," he said. He made it clear that testing of 11-year-olds would continue, to cries of "rubbish" from the audience.
Mike Welsh, a headteacher from Swindon, responding to Mr Balls's speech, said: "We have won the educational argument [on the tests]... Please, please, please do not test our resolve on this issue."
Central to the heads' concerns is their worry that the tests have distorted the school curriculum – particularly for 11-year-olds.
They say there is too much "teaching to the test" because of worries about how schools will fare in primary school league tables. A poor showing can cost a head their job.
Leaders of both the NAHT and NUT say they are ready and willing to talk to ministers about what should replace the tests.
Ideas that have been put forward include a suggestion from Durham University's Professor Peter Timms, one of the country's most highly regarded experts on assessment, that a sample of pupils should be tested every year to give a picture of how standards in primary schools are faring.
Dr Chris Howard, president of the NAHT, said of the tests: "They serve no educational purpose.
"There will be no conclusion to our honest and well-reasoned campaign to stop the tyranny of tests and league tables for primary schools in England until they have been ended."
The vote on the boycott was taken just an hour after Mr Balls had finished speaking to the conference. Ministers have argued that a boycott by headteachers could be illegal, as they have a duty to deliver the tests.
The NAHT believes it can argue in favour of industrial action on the grounds of the effect that the tests have on their workload.
Last year, when the results were delayed as the US-based firm hired to deliver them failed to meet its deadline, concerns over marking standards led to heads making an unprecedented 155,000 appeals against the results.
Mick Brookes, general secretary of the NAHT, has argued that heads have "a moral duty" to scupper the tests because of the negative impact they have on children's learning.
He insisted the time is now right for "civil disobedience" over testing, saying this can sometimes be justified to secure an end. Without it, he said, women might never have won the vote or India become a free nation.
The Government has set up an "expert group" to review testing and assessment arrangements in schools – expected to report later this month.
However, while Mr Balls has said the present testing system is not "set in stone", he has also said he does favour some testing mechanism for children at the end of their primary schooling.
Last night's decision is a devastating blow to Mr Balls, who changed his schedule to address the headteachers before they took the vote.
Mr Balls has described himself as being "between a rock and a hard place" over the tests, as one of the other teachers' unions, the National Association of Schoolmasters Union of Women Teachers, has warned it may take industrial action if he scraps them. It argues that if externally marked tests are replaced by teachers' own assessments, it will involve teachers in more work.