The head of London’s strictly Orthodox rabbinate has signed a petition urging defiance of plans by New York city health authorities to regulate a controversial circumcision practice.

Rabbi Ephraim Padwa, leader of the Union of Orthodox Hebrew Congregations, is one of 200 rabbis who declared it “forbidden” to accept the move by the civil authorities.

Health authorities have become concerned at the practice of metzitzah b’peh in which immediately after a brit, the mohel sucks the baby’s glans to draw blood from the wound.

In most circumcisions today, the mohel uses a glass tube to perform the practice.

But in many Chasidic communities, the mohel sucks the wound directly without the use of any instrument, carrying increased risk of transmitting herpes, according to health authorities.

According to the Forward newspaper, there have been 11 cases since 2000 of babies contracting herpes after a brit where direct suction took place, causing two fatalities.

New York City Health Department will next week vote on a proposal to allow direct suction only with written parental consent.

But the planned measure had been denounced by the 200 signatories of the petition as an “evil degree” that seeks to interfere in an age-old tradition.

Accusing the health department of spreading “lies and exaggerations” of the instance of illness after metzitzah b’peh, they declared: “It is clear to us, that there is not even an iota of blame or danger in this ancient and holy custom.”

They said it was forbidden “according to the Torah to participate in the evil plans of the NYC Health Department in any form that it may be whether it be the mohelim, or the parents – with agreements or signatures”.

They warned that this was “only the beginning of their decrees, for their plan and desire is to undo the foundations of brit milah in its entirety”.