Michael O'Keefe, of Anderton Park primary, in Birmingham, sent a letter warning parents of the fine after he moved the school's closing time from 3.20pm on Fridays to 2.20pm. He claimed that the early finish was necessary to complete building work and said the cash from fines would be used to fund extra "childcare".
In a letter to parents, Mr O'Keefe said: "We will be charging you pound;20 for childcare if you are late for your children. We would also need to contact the police andor social services."
But following objections from parents, some of whom would be at the mosque at 2.20pm, Friday's finishing time has returned to 3.20pm and the fining scheme has been dropped. Mr O'Keefe was unavailable for comment.