my nephue is toilet trained but wont use it at school

[sarahc131013]

my mum has full time care of my nephue and he has been potty trained for the past 2 year. but now he has started school and refuses to use the toilet. the teachers keep asking if hes still in nappys at home and making out my mum is lieing he has mild learning difficultys but understands perfectly and when my mum tries to tell him he has to use the toilet at school he laughes at her. the teachers take him to the toilet now n he goes in but five mins later he wets him self asif hes hone but not uswd the toilet. my mum thought he might have a problem but over the holidays he didnt have a single accident its just at school. Has anyone been through a simalar thing.