The 11 Church of Iran members had been charged with “action against the order of the country” and drinking alcohol, after joining a house church meeting and taking communion wine.

The churchgoers were arrested in April and brought before the Revolutionary Tribunal in Bandar-Anzali for a rushed hearing on May 1.

In its written verdict, the court determined that the group were taking part in a Christian ceremony and therefore within their rights under Article 13 of the Iranian Constitution, which allows Zoroastrians, Jews and Christians to “perform their religious rites and ceremonies, and to act according to their own canon in matters of personal affairs and religious education”.

According to Christian Solidarity Worldwide, the judge concluded that there was no evidence to suggest that the group had been acting against national security or the order of the country.

The local authorities have 20 days to appeal the decision.

CSW's Chief Executive Mervyn Thomas said: "In a climate where evangelical Christians are regularly targeted by the regime, this acquittal is a very welcome development.

“It is unfortunate that although the Iranian constitution clearly states that Christians are a protected minority, such protection is denied to any who do not belong to Iran's traditional churches.

“We commend the judge in this case for ensuring due process, and for recognizing that these people belong to a Christian denomination, so the exercising of their faith poses no threat to the country.”

The eleven acquitted Christians are Pastor Abdolreza Ali-Haghnejad and his wife Anahita Khademi, Mahmoud Khosh-Hal and his wife Hava Saadetmend, Fatemah Modir-Nouri, Mehrdad Habibzade, Milad Radef and Behzad Taalipas, and Amir Goldoust, his sister Mina Goldoust, and his grandmother Zainab Bahremend.

CSW remains concerned over the fate of six other members of the Church of Iran in Shiraz, who are still awaiting the outcome of a consultation on their case.

The six were charged with blasphemy but a hearing on their case was postponed to allow the prosecution more time to consult Iran’s traditional churches on the validity of the charge.

One pastor in the Church of Iran, Yousef Nadarkhani, is in prison awaiting the outcome of an appeal against his death sentence for apostasy.

Mr Thomas said: "We continue to urge the acquittal of the six in Shiraz, whose charges are baseless, and of Pastor Nadarkhani, whose death sentence is an appalling violation of the right to freedom of religion and belief, which, as a signatory of the International Covenant on Civil and Political Rights (ICCPR), Iran is obliged to uphold.”