The proposed hanging of Youssef Nadarkhani is an outrage. It is also a terrifying glimpse of the injustice and arbitrary cruelty of the present Iranian regime. This paper opposes the death penalty always and everywhere, but at least when it is applied for murder or treason there is a certain twisted logic to the punishment. But Mr Nadarkhani's crime is neither murder nor treason. He is not even a drug smuggler. He is just a Christian from the city of Rasht, on the Caspian Sea, who refuses to renounce his faith. There is a pure and ghastly theatricality at the heart of this cruel drama which goes to the heart of religious freedom.

There is no question that Mr Nadarkhani is a Christian, and an inspiringly brave one. That is, in theory, legal in Iran. The particular refinement of his persecution is that he is accused of "apostasy". The prosecution claimed he was raised as a Muslim, which is why his present Christian faith merits death. He was convicted last year. Mohammad Ali Dadkhah, the lawyer who was brave enough to defend him, was himself sentenced to nine years on trumped-up charges this summer. Both these sentences are offences against natural justice. Both were appealed. The supreme court in Tehran last week announced its judgment on one: Mr Nadarkhani might save his life if he publicly renounced Christianity. This he has twice this week refused to do. A third refusal – due at any moment – might spell his death sentence.

Apostasy, even more than blasphemy, should never be a crime. The right of an adult to choose his or her own beliefs is the freedom which above all others makes them adults. That is one of the great discoveries of civilisation – the awkward and often painful process of learning to live together in larger and more inharmonious groups than families or clans. All across the Middle East, this foundation of tolerance is systematically denied.

Whether by torture, pogrom, or the occasional judicial murder, the persecution of religious minorities in Iran, in Saudi Arabia, and in Pakistan, is a recognised way for failing authoritarian regimes to appeal to the more revolting instincts of the people they hold down. Christians, Jews and Bahá'ís are persecuted everywhere. In Iran the Sunni minority has no mosque in Tehran, where a million Sunnis live. In Saudi Arabia and Pakistan, the Shias in their turn are persecuted and suppressed.

Everywhere, the general terror of a people who can make up their own minds freely about anything is blended with a horror of people who can make up their own minds about religion. These laws are an insult to God, to Islam, and to our humanity. The sentence against Mr Nadarkhani shames Iran.