Labour has announced plans to abolish primary school Sats.
Speaking at the National Education Union’s Conference in Liverpool, Jeremy Corbyn set out proposals to scrap the “regime of extreme pressure testing”.
Labour said the policy would relieve pressure on a schools system forced to cope with overcrowded classrooms, and an ongoing crisis in teacher recruitment and retention.
Currently primary schoolchildren undertake national curriculum assessments - otherwise known as Sats - in English, maths and science at the end of Year 2 when aged six or seven, and again at the end of Year 6, aged 10 or 11.
Mr Corbyn said: “We need to prepare children for life, not just for exams.
“Sats and the regime of extreme pressure testing are giving young children nightmares and leaving them in floods of tears.
“I meet teachers of all ages and backgrounds who are totally overworked and overstressed.
"These are dedicated public servants.
"It’s just wrong.”
Mr Corbyn also announced that the next Labour government will scrap baseline assessments for reception classes.
He said Labour would consult parents and teachers on an alternative that “prepares children for life, not just for exams”.
The conference heard: “Our assessment will be based on clear principles.
"First, to understand the learning needs of each child, because every child is unique.
“And second, to encourage a broad curriculum aimed at a rounded education.
“When children have a rich and varied curriculum, when they’re encouraged to be creative, to develop their imagination, then there’s evidence that they do better at the core elements of literacy and numeracy too.”
Mr Corbyn said his party trusts teachers and will raise standards by freeing them up to teach.
He added: “Teachers get into the profession because they want to inspire children, not pass them along an assembly line.”
Dr Mary Bousted, joint general secretary of the NEU, said: “Jeremy Corbyn gets it – he recognises the damage that a test-driven system is doing to children and schools; he understands what needs to change; he sets out ideas for education which will make sense to parents and teachers.
“The NEU has long advocated an assessment system that has the trust of teachers and school communities – one that will support children’s learning and raise standards of attainment in our schools.
“We look forward to the return of a broad and balanced primary curriculum and to the rekindling of the spirit of creativity in our schools.
"We welcome Labour’s commitment to work with the profession in order to develop these ground-breaking policies further.”
Last year, the Government announced that Key Stage 1 Sats would be replaced with a new baseline assessment in reception beginning in 2020.