Clegg attacked the current education system, saying it was a "one size fits all" approach and that the government was failing thousands of children by not giving them a personalised education.

He also pledged to give all schools the same freedoms academies currently have.

Clegg said the Lib Dems would also cut the size of the Department for Children, Schools and Families and create an independent education standards authority, which would incorporate Ofsted.

"Ministers would have to stop sending their regular diet of directives and diktats to schools," he said. "We need to strip ministers of their power to meddle and micro-manage."

Money saved by scrapping testing would be put into early assessment at age five and one-to-one reading and maths tuition.

Clegg also said targets should be changed to address the needs of all pupils, not just borderline pupils.

Mary Bousted, general secretary of the Association of Teachers and Lecturers, said: "Much of what Nick Clegg says will be music to teachers' ears. However, he doesn't say anything about scrapping Key Stage 2 tests although they are of little use."