Britain's biggest headteachers' organisation is threatening a national revolt against tests for seven, 11- and 14-year-olds and exam league tables.
Leaders of the National Association of Head Teachers are considering industrial action to stop the Government compiling the league tables.
They are planning to ballot heads on refusing to supply test results to the Department for Education and Skills. In addition, they want to persuade parents to keep their children away from school when national curriculum tests are sitting.
Mick Brookes, the NAHT's general secretary, said this approach had been adopted at his former primary school in Nottingham. If less than two-thirds of the pupils turn up, the results are invalidated.
Delegates to the NAHT's annual conference in Harrogate yesterday unanimously backed a motion calling on the Government to scrap the tests - sat by two million pupils every year - and league tables.
Rona Tutt, a former president and headteacher from Hertfordshire, said: "The Government seems to be determined to hang on to its money-squandering regime of targets, tables and tests."
It had also introduced tougher targets for five-year-olds - outlined in a speech from Ruth Kelly, the Education Secretary, last week.
"There is pressure on our children over the key stage- one tests [for seven-year-olds] at a time when pupils in other countries are just beginning their formal education," Ms Tutt said.
"This fixation with test results not only crowds the curriculum but ignores the talents of late developers."
If today's testing regime had been applied to Winston Churchill, Albert Einstein and Sir Isaac Newton, they would have been written off as dunces because they were late developers.
Mrs Tutt added: "Missing targets does not mean a school or child is failing.
"If it did, the Department for Education and Skills would be in trouble, except of course they just postpone their targets when they're in danger of missing them or they become aspirational targets instead."
Earlier, delegates had heard that one in four heads were considering quitting because of the pressure to perform well in school league tables. One warned that heads were suffering from "football manager syndrome" - forced to carry the can if targets were not met.
David Willetts, the shadow Education Secretary, was greeted with cries of "no" when he defended league tables at the conference by saying: "I wouldn't abolish the publication of league tables because now people expect that sort of information."
But he won applause when he sided with heads over complaints about the new inspection system introduced by Ofsted, the education standards watchdog.
He also criticised ministers for boycotting the NAHT conference because heads had pulled out of an agreement to reduce teachers' workload.
"I think it is childish - absolutely absurd - that we don't have ministers here today," he said.
Mr Brookes said later he would be consulting with other groups such as teachers' unions and parents over mounting a joint campaign to scrap the tests and league tables. He said any action would have to wait until next year - as this year's tests are just about to start. A spokesman for the DfES said last night: "Tests and league tables are a non-negotiable part of our education reforms."
* Schools will be barred from asking about the private lives of the parents of potential pupils under a tough new code to outlaw selection by stealth. The code, which will be legally binding, also tells school governors they must ensure uniforms are widely available at a reasonable price and not just from an expensive sole supplier.Reuse content