Ofsted inspectors have strongly criticised a Yiddish-speaking Chasidic school in Stamford Hill for providing an "inadequate" education.
Talmud Torah Chaim Meirim Wiznitz - a primary school for 242 boys aged mainly from five to 13 which is associated with the Vishnitz sect - was instructed to make improvements after an emergency inspection in January.
But inspectors who returned to the school in June found that pupils were still not receiving proper tuition in secular subjects.
"Teaching is inadequate and… pupils do not have access to a sufficiently broad and balanced curriculum," Ofsted reported. "Not all pupils have the opportunity to learn English as an additional language, as required, given that English is not the first language of the pupils and it is not the language of instruction throughout the school. This means that pupils are not prepared sufficiently to be able to make progress in their continuing education, nor for the opportunities and responsibilities of adult life."
Boys in year one and two did not study secular subjects, while secular classes for those in year five to eight amounted to just an hour-and-a-half out of a 10-hour school day. "Lack of time and the limited resources used mean that pupils do not make the progress they should in either mathematics or English."
Inspectors found a lack of proper tuition in secular subjects
Religious studies did provide some insight into other subjects, such as history and geography, and the school had begun making changes so that all pupils received a balanced education.
"New teaching has recently been introduced to ensure that pupils learn about British institutions and values," Ofsted noted.
"This includes, for example, the role of the monarchy, the way government works, the importance of the rule of law and an attitude of tolerance." But there were no PE classes.
Ofsted also noted that the school's leaders and owners were insufficiently aware of independent school regulations and had failed to carry out all the necessary checks to ensure that all staff were suitable to teach children.
A school representative declined to comment.