Teachers have backed a boycott of new literacy and numeracy checks for infants amid warnings that four is too young to test.
Delegates at the National Union of Teachers’ conference called for the tests, which are coming to many schools in September, to be abolished.
They claimed children are being subjected to death by testing.
However, schools minister Nick Gibb hit back, saying it was extraordinary that teachers’ unions could not say a single positive thing about England’s schools.
Under the outgoing Government’s reforms, from September 2016, infants will undergo literacy and numeracy checks just weeks after they start in reception.
The results will be used to chart children’s progress throughout primary school.
Ministers have insisted that the move will help ensure children leave primary school with a good standard of reading, writing and maths.
But there were cheers at yesterday’s conference in Harrogate as delegates took to the stage to voice their opposition to the assessments and make calls for action.
Sara Tomlinson, an NUT member from Lambeth, south London, said: “We have got a chance to stop these tests and we need to step up this campaign and we need to act pretty urgently as a trade union to make sure we stop these tests becoming part of the school routine.
“The first reason is that four is too young to test.”
One example question for the baseline assessments is to ask a child to say “parrot”, and then ask them to say it without the “p”, Ms Tomlinson pointed out.
“What skill is it to be able to say ‘arrot’?” she said. “This is the craziness of the test.”
A resolution put forward at the conference argued that the primary curriculum is overcrowded and restrictive and that a focus on high-stakes testing is having a negative impact on children’s education.
It called on the union’s executive to take action, including “working towards a boycott of baseline assessments”.
An amendment, which was also approved, said: “Conference agrees to begin a campaign towards a boycott in the summer term 2015, in time for members to be able to boycott the baseline assessments in the summer of 2016.”
NUT officials said later that they are seeking a national U-turn over the assessments.
If that fails, there would be a move towards a ballot for a boycott in the summer of 2016.
Helen Pope, a newly qualified reception teacher, also from Lambeth, received loud cheers as she told the conference she would be refusing to do the tests at her school this September.
She said: “It’s no wonder that four in 10 new teachers leave within their first year of teaching when our principles are attacked on this grand scale.
“But unfortunately for whoever takes over as education secretary, I am one of the 60% of new teachers who will be staying.
“I will be going back to my school in September and welcoming my new class and with the backing of this union I refuse to do your tests.”
Jennifer Harper, from Wandsworth, south London, said her niece will be four years and two weeks old when she is expected to take the new checks.
“The thought of her jumping along to school with her new book bag in hand, her new school uniform on ready to play, paint, to explore the world and start her love of learning should be what we are looking forward to.
“Instead I know she will be puzzled by being asked lots of questions about parrots or sat in front of a computer that she will not have much experience of because she prefers making and doing.
“This is not the start of her education and learning that anyone can be proud of.”