More than 100 teachers, writers and academics have said the government's early years education policies are damaging children's health and wellbeing.
The education specialists have written to the secretary of state, Michael Gove, to demand that children be allowed to learn through play instead of being prepared for formal lessons at such an early age.
Signed by 127 senior figures including Lord Layard, director of the wellbeing programme at the London School of Economics, and Sir Al Aynsley-Green, the former children's commissioner for England, the letter in the Telegraph says current research "does not support an early start to testing and quasi-formal teaching, but provides considerable evidence to challenge it".