Chief Rabbi Ephraim Mirvis celebrated a "red-letter day for everyone in British Jewry" at the opening of its newest state-aided school - the Yavneh Primary in Borehamwood, Elstree.
The new free school, sited behind its older sibling, Yavneh College, will operate from portable classes for two years until a permanent building is erected.
A full complement of 60 children will begin learning in earnest on Monday, split into two classes, zeraim or "seeds", and nitzanim, "buds".
But they and their parents had a chance to inspect their new classrooms on Friday as the Chief Rabbi and others affixed the first mezuzot.
Spencer Lewis, executive head of Yavneh schools, said, "I look forward to watching you grow from seeds and buds to big strong trees".
For local parents, the school has come not a moment too soon with other Jewish schools in Hertfordshire oversubscribed.
Victoria Rose, whose four-year-old daughter Bella is among the first intake, said she had been "petrified" before Yavneh's opening was confirmed because she had not been able to gain a place at other north-west London Jewish schools.
"We're so excited," she said, "We know how much effort went into setting this up. For her quality of life, having a school on her doorstep makes a huge difference."
Poppy Brent's father Marc added that he thought the family were "very fortunate.
"We wanted a Jewish education for Poppy and we had been worried about the prospect of her having to travel miles to school," he said.
Although a free school can currently only guarantee half its places on the basis of faith, most of Yavneh Primary's students are Jewish,
However, a number of local non-Jewish children will also be attending, including Josiah Berko. "I so wanted him to come," said his mother, Gifty Anim, who is Christian. "And he wanted to come. With faith comes values and having values is important to me. The children have something to live up to."
Malcolm Gordon, chairman of the Yavneh Foundation, admitted: "I did find it difficult not to cry when I saw the first child here this morning."
He recalled that it was 10 years ago that the college's first pupils walked through the gates.
"If anyone had predicted then that the college would be adding a bulge year and opening a primary school a decade later, I would have said they were mad."