Concerns have been raised over the number of pupils that are now being crammed into classrooms across England.
A baby boom has seen the number of five- to seven-year-olds studying in lessons with more than 30 pupils double to 10,000 in just two years.
Department for Children, Schools and Families (DCSF) figures released this week show that primary schools are bursting at the seams with one in 10 pupils aged four to 11 is in a class of more than 30.
This is double the number two years ago when just 4,280 primary school pupils had in excess of 30 classmates.
Christine Blower, general secretary of the National Union of Teachers, said: "For all those primary teachers who are now facing the impossible job of fully responding to each child's needs in excessively large classes, this deterioration is a blow both to their stress levels and to teaching and learning."
Experts suggest that children in smaller classes perform much better than those learning in a more crowded environment.
