The ruling came after parents won a three-year legal battle with the local authorities over a crucifix in Macias Picavea school in Valladolid, northern Spain.
The Valladolid Cultural Association for Lay Schools argued that crucifixes infringed the 1978 Constitution, which establishes Spain as a non-denominational state but recognises individual religious rights.
Judge Alejandro Valentin Sastre ruled that “the presence of religious symbols such as a crucifix is an element of aggression which infringes rights and freedoms”.
The courtroom victory came late last year and has reignited a debate about the place of religious symbols in what was once one of Europe’s most devoutly Catholic countries. Ten years of one of the fastest rising rates of immigration on the Continent has increased the number of Muslims, Protestants and other religions in Spain.
And amid discontentment with the right-wing stance of Catholic hierarchy in Spain, many people are leaving the Church.
Fernando Pastor, 47, whose six-year-old daughter attends the school, led the secular campaign. “What stunned me was not so much that the cross was nailed to a wall but that it was at the head of a public educational activity which was not confessional,” Mr Pastor said.
The Episcopal Conference, the ruling body of the Roman Catholic Church, condemned the ruling. Archbishop Carlos Amigo, the Cardinal of Seville, said: “The most important thing is to educate the children to respect religious symbols of all types.”
The Catholic Confederation of School Parents said that the ruling was symptomatic of a “campaign of rabid secularism against religious symbols”.
The issue is likely to remain because the Spanish Government is preparing to reform its Law of Religious Liberties to give an official voice to other religions. Secular groups have been campaigning for years to remove any trace of the Church, which was seen by the Left as a political ally of the Franco dictatorship.
The secular cause has found an unlikely ally — a Catholic priest. Father Florentino Escribando Ruiz, from Badajoz, western Spain, suggested that crosses should be replaced with photographs showing suffering children from around the world.