A judge has upheld the right of a former Satmar Chasid to have his young children to stay over Shabbat and festivals despite complaints from the mother he did not keep to religious requirements.

She alleged he had let the children, who cannot be identified, ride bikes and watch TV on Shabbat and let them eat non-kosher food.

But Judge Judith Rowe found that while the father may have occasionally deviated from strict standards of observance, he had not deliberately flouted the religious rules of the strictly Orthodox sect.

The man moved out of the Satmar community three years ago, leaving the mother fearing her two children would be "exposed to an alien way of life" when they went to stay with him.

In May this year the father applied to the courts to enforce an earlier ruling that the children should be able to stay with him on festivals.

But a month later the mother sought an order to stop him having the children for Shabbat and festivals.

In a third hearing in two years, Judge Rowe said the parents had reached agreement that the children could spend Yom Kippur and Shavuot with the father and Rosh Hashanah and Purim with their mother.

The judge ruled that the father should continue to have the children on alternate weekends and the children should spend "equal time with each parent" for Pesach and Succot.

While the father accepted some of the mother's allegations, Judge Rowe found "he would not do something as fundamental to any observant Jew as to give these children non-kosher food".

The judge, sitting in a session of the West London family court in Barnet, added: "Given the Satmar difficulty – and the mother's difficulty - in acknowledging that the father is still Jewish, it is vital for these children to see that he is.

"To that end, they must spend important religious days with him just as with the mother."