Stamford Hill Charedim have raised £1 million to fight legal cases where they think children are at risk of being removed from the community by one of their parents.
Over 1,500 people attended a meeting last week to establish a fund to help "rescue the holy children from descending into ruin" in cases where parents are fighting a custody battle and one wants to leave the strictly Orthodox community.
The JC understands that there are four or five ongoing cases involving these children.
Rabbi Ephraim Padwa, the spiritual head of the Union of Orthodox Hebrew Congregations, published a letter in support of the cause. He referred to "17 of our pure and holy children, where one of the parents has chased after a wicked culture and want to drag their children after them."
A representative of Gesher EU, an organisation that helps those who wish to leave the Charedi community, said the move would engender fear.
The spokesperson added that it was one of "the tactics used by the Charedim to try to prevent people leaving the community by denying them access to their children.
"Knowing that the community can draw on unlimited funds to support an ongoing legal battle over custody can be daunting, to say the least."
However, a spokesperson for the Stamford Hill community said the issue was "very serious and sensitive".
He added: "People usually wouldn't give this money for just anything, but this is unique case. We can't dilute Yiddishkeit - we have to keep ourselves strong together."
Over £600,000 was raised at the meeting at the Bobov synagogue, where the crowd was addressed both by local rabbis and the grand rabbis of three Chasidic sects - Vizhnitz, Slonim and Rachmastrivka - who had flown in for the occasion.
Earlier in the day the grand rabbis had met affluent members of the community. It is understood that following the meeting, the £1 million target was reached. Posters advertising the event urged participants to give at least £500, with the option of paying in instalments.
Those who gave £5,000 or more were promised a "certificate of partnership", signed by the visiting dignitaries. Rabbi Padwa's letter also referenced shmad, which is the Hebrew word for "apostasy".
Divorce is frowned upon within the strictly Orthodox community, and custody battles in court are comparatively rare.