A state-aided Charedi school will have to change its admissions procedure after the body which regulates admissions said bans on “very long skirts” and on dressing in “flashy” colours were too vaguely worded.

But the Office of Schools Adjudicator said the Yesodey Hatorah Senior Girls’ School in Stamford Hill was within its right to demand that children should not have access to the internet as a condition of entry.

Following a complaint from an individual, the OSA ruled that several requirements in its lengthy dress code fell foul of the admission code for schools because they were not sufficiently clear.

As a result, the school has proposed removing references to “very long” skirts and “flashy” colours, while specifying that the prohibition on “trendy” fabrics means leather and lycra.

The OSA objected to a requirement for “discreet” make-up because the description “does not allow for a single, objective understanding”. The regulator also took issue with the current system of asking a rabbi from the Union of Orthodox Hebrew Congregations to confirm the religious practice of families who apply.

Rabbis could not have first-hand knowledge of every aspect of a family’s compliance with the school’s religious requirements, the OSA said. A rabbi’s confirmation “should be restricted to what might be termed ‘public’ practices that can be objectively assessed”.

It also said the school could not require that the father of a pupil belongs to a Charedi shul. It was allowed to say he must pray at one, since schools may use only synagogue attendance, not membership, as an entry criterion.

But the OSA did not believe it unfair for the school to reduce its annual entry limit from 80 to 65 and to lower the age of entry from 11 to nine next year.

The school was placed in special measures a few weeks ago after receiving a highly critical Ofsted inspection.