The ECHR couldn't have got this more wrong.

I am, unsurprisingly, a supporter of the European Court of Human Rights. But, this decision to overturn a previous ruling banning the display of crucifixes in Italian schools is wrong, wrong, wrong! In the first place the fallout of the latest decision doesn't just cover Italy, it is binding on all 47 countries that are members of the Council of Europe, which of course includes the U.K. But its reasoning is so illogical as to make me ashamed to be a supporter of this usually rational institution.
For example

11.6 Moreover, with the benefit of hindsight, it is easy to identify in the constant
central core of Christian faith, despite the inquisition, despite anti-Semitism and
despite the crusades, the principles of human dignity, tolerance and freedom,
including religious freedom, and therefore, in the last analysis, the foundations of the
secular State.

Which is an argument they use to justify a claim that the crucifix is a cultural symbol and not a religious one.
I call bullshit! Despite the inquisition? Despite anti-semitism? What person with any humanity would want to pin their cultural heritage on such a bloody symbol. Let's be clear, the enlightenment, as far as we have it, has no basis in christianity. If anything religion has fought against our instincts to be inclusive and co-operative since Adam was a non existent juvenile.
This is one of the areas where the U.S has a legal defence in the non establishment clause in their constitution. Admittedly it's a battleground over there but the legal precedents exist and can be defended by committed secularists. In Europe, a notionally less theistic region (particularly in the northern countries) those church/state separation clauses are not written into law, which is why bodies such as the European Court of Human Rights should be very, very careful in these cases.
Europe, all of it, is becoming more and more multi-cultural, so this is not about subjecting children to any old religion in the classroom, undesirable as that may be, but about the effect of having specifically Christian symbols around children who identify as Muslim, Hindu, Jewish or any number of other “cultural” religions. It sends a message to these kids that they are “other” and outside of the mainstream culture they find themselves in.
School is not the place for this sort of message and the court has got this badly wrong. I hope there is a route of appeal, this should not be allowed to stand.