BBC's World's Strictest Parents 'do Shabbat & keep kosher'

They were chosen to take part after dropping out of their A-level courses and because of behavioural issues at home.

Previous episodes of the show have featured youngsters learning about discipline and educational values with born-again Christians in Alabama and Afrikaaner families in South Africa.

Tzippi Sha-ked said she and husband David had found the filming “turbulent at times and definitely filled with hiccups”, but believed the process was mutually beneficial for their five children and the British teens.

“We wanted to explain the philosophy of self-respect. Gemma was used to parading around in very few clothes. We introduced them to a very different lifestyle,” she said.

When told about kashrut laws the teenagers were “extremely surprised and shocked. Their reaction was ‘we cannot do any of that’. But by the end of the week they also kept Shabbat in its entirety. I think it was the first time they had gone half an hour without a smoke, let alone all day.

“They both came with a nasty habit of peppering their everyday speech with foul language. But by the end of their stay I don’t think there was one bad word.”

During the stay, Gemma told the Jerusalem Post how she had ditched wearing a bikini in the hot weather to adopt a more considerate dress-code.

She said: “I think you need to respect yourself and if you cover up you are respecting yourself.

“When you get into a relationship, it’s something special between yourself and the boy.”

The transformation, Mrs Sha-ked said, would also be felt following Gemma’s return home: “She told us she wants to incorporate Shabbat values into her life, albeit on a Sunday, and have special family time without driving or telephones.”

Jack’s “Goth” appearance was out of step with the rest of the community’s dress-sense. He had “quickly realised it would not do to wear eyeliner and lipstick” during the trip, Mrs Sha-ked added.

Jack said visiting Jerusalem and the Western Wall had been “amazing” and the highlight of his trip. The family have received emails from him saying how much he misses Israel since returning home on Sunday.

Mrs Sha-ked said: “We did not intend to convert them. It was an opportunity to articulate and display a Torah lifestyle and make a difference. We saw such a change. They are now an extension of our family.”

Carolyn Payne, series producer for Twenty Twenty Television, said the week had gone “brilliantly” and filming in Nof Ayalon had been “a real coup”.

“Previously the family lived in LA and had helped teenagers there, so they were completely into the idea of the show,” she said.

“They had some very strict rules which we had not come across before, such as men and women not touching each other until they are married. That is totally alien to us [in Britain].”

Gemma and Jack developed friendships with the older Sha-ked children — Matan, 18, and his sisters Ziona and Tehila — and plan to keep in touch.

The episode of World’s Strictest Parents featuring Jack and Gemma is due to be screened on BBC3 in August.

BBC's World's strictest parents