How fair are entrance criteria to Jewish schools? It's a question that has continually challenged Anglo-Jewry, culminating in the traumatic JFS case.

Unfortunately, there may be further trouble ahead. A horror story has developed at Clore Shalom, a pluralistic primary in Shenley, which may have radical implications for others. Ironically, the attempt to carve out a fairer entrance procedure looks likely to worsen the situation.

A couple whose child had not been accepted into the nursery challenged the school's admissions criteria for the reception class, arguing that it was unfair to give priority to children who belonged to a synagogue or who had attended its nursery. After the adjudicator upheld the appeal, the school announced that five children in the nursery would not receive priority and their chances of getting into reception were negligible.

The families involved argued that the change need not take place until next year, when a new cohort would enter the school, fully aware their places were not guaranteed. To no avail. Their four-year-olds are effectively going to be expelled.

This week, Clore revealed that the Education Secretary, Michael Gove, is considering whether the school's actions were sufficient to comply with the adjudicator's decision, potentially affecting more children.

The result will be heartbreak for dozens of families

Who is to blame? The adjudication process is completely inconsistent. While Clore's admissions have been ruled unfair, two other Jewish schools have been told that nursery places are valid criteria for reception. But rulings for one school do not apply to another.

The parents who originally made the complaint are entitled to seek a Jewish education for their child, but they must have known that success could only come at the expense of current pupils. As for Clore itself, it ignored the implications of the JFS case, which made shul membership a legally risky criterion. Its governors failed to inform parents (and the new head) until weeks after they found out about the problem, and then acted with undue haste even when doubts were raised about when the decision had to be implemented. Why they are still in place is a mystery.

But now Clore's problem is potentially everyone's problem. Since most Jewish schools give priority to nursery pupils when selecting a reception class, and many do not open up extra spaces, what is to stop parents who do not get into their chosen nursery challenging these schools on their reception criteria? Even if not all are upheld, the result will be heartbreak for dozens of families.

Schools wishing to pre-empt this could each year refuse to guarantee the places of some nursery children - as proposed by Hertsmere Jewish Primary School, which is suggesting giving priority for its 2014 reception class to only 50 of its 60 nursery children, some of whom would be selected randomly. This would destroy the cohesion of the nurseries, mean unnecessary upheaval and ultimately create a disincentive to send children to Jewish nurseries. Another suggestion at a recent Board of Deputies meeting was that schools reduce the size of nursery classes, to allow newcomers to join reception.

This, however, would be a financial hit for the schools, which may depend on income from the private nurseries. The squeeze on nursery places would worsen, and not result in any extra children being admitted to Jewish schools. A small number who, under the current system, would have got into the nursery would simply start a year later.

The long-term danger is that maintaining a place at a Jewish primary is going to become so complicated that less committed parents are not going to bother. The ruling lays a minefield for the community, which may yet make the JFS case look tame by comparison.