The number of pupils per teacher is unacceptably high in some nursery classes, says a survey from the National Union of Teachers.
Government guidelines for nursery education recommends that 26 nursery pupils should have at least two teachers, one of whom should be a qualified teacher.
But the survey of headteachers in a random sample of 203 nursery and primary schools found that one group had only one teacher and one nursery nurse for 37 pupils.
Overall, the pupil/teacher ratio broke the guidelines in a quarter of the sessions.
Union leaders said that the nursery teachers' workload was worrying because the Government wants all teachers of under-fives to work towards new goals.
From September next year all schools will have to assess children according to set criteria. Guidelines on what children should know and be able to do by the age of five (or "desriable outcomes") have been drawn up by government curriculum advisers.
Teachers will have to record pupils' achievements and tell parents about their progress.
Because most nursery education is part-time, the vast majority of nursery teachers have two teaching groups a day.
The survey found that almost 58 per cent of nursery teachers have responsibility for between 40 and 85 children. 2.6 per cent have responsibility for more than 100.
The union wants a legal limit placed on the number of children for whom one nursery teacher can be responsible.
It is also concerned about children with special educational needs whose difficulties must be identified early if they are to be remedied.
Two classes in the survey which covered 350 teachers and headteachers had no qualified teachers. In each case, one qualified nursery nurse was in charge of 26 pupils.
In Luton, one teaching group had one teacher, one part-time nursery nurse and one part-time assistant for 39 pupils.
Doug McAvoy, the union's general secretary, said:``A teaching group of 37 cannot be regarded as providing an acceptable level of educational support to children. The Government must ensure that provision for such young children is protected.
``Given the range of duties required of nursery teachers, there must be constraints on teachers' workload. If teachers are to ensure the Government's desirable outcomes are achieved, a limit must be placed on the number of pupils for which an individual nursery teacher is responsible. Nursery education gives children a flying start. Their prospects must not be diminished by over-loading their teachers.''
David Blunkett, the Secretary of State for Education, has promised that every four-year-old will have a nursery or school place by September next year. Local authorities are drawing up plans for early years education in consultation with private schools and voluntary groups.Reuse content