A Sky News investigation finds that hundreds of pupils, some as old as 15, are unable to use a toilet on their own at school.
Children are still wearing nappies in class after the age of five in hundreds of schools across the country, a Sky News investigation has found.
Teachers have reported pupils as old as 15 who have no medical conditions or developmental issues, but who are unable to use the toilet on their own.
In what is believed to be the first survey of its kind, Sky News commissioned the National Foundation for Educational Research to ask head teachers and staff in England about their experiences of children coming to schools wearing nappies.
Almost one in 10 heads and senior staff who responded said in the past year a child aged between five and seven had worn a nappy to school.
The figure was 5% for classroom teachers.
Almost one in 20 heads and senior staff said that in the last year a child aged seven to 11 had worn a nappy to school.
And 1% of classroom teachers surveyed had experience of older children in nappies.
The survey was completed by 602 teachers in primary schools and 561 teachers in secondary schools.
The figures suggest that head teachers and senior staff at a substantial number of England’s 16,000 primary schools have experience in the past 12 months of at least one pupil above the age of five still wearing nappies.
There has been growing evidence in recent years that increasing numbers of children are starting school in nappies.
But this is the first research to suggest the problem extends beyond the Reception year.
And experts say it is not just pupils from deprived backgrounds who are not being toilet trained, but those who have working parents too busy to address the issue.
Anne-Marie Middleton, a deputy head teacher from Dover, says many pupils are too embarrassed to admit they still wear nappies.
She said: “We’re seeing more and more children wearing nappies. We find that more and more children have an issue with toilet (training) further up the school.
Ms Middleton says that the busy lives of parents are often at the root of the problem, with pupils arriving at school without many basic skills including toileting, or being able to use a knife and fork.