The charges relate to the group's involvement in a house church meeting and taking communion wine.

According to Christian Solidarity Worldwide, the group was suddenly brought before the Revolutionary Tribunal in the Iranian city of Bandar-Anzali on May 1.

The church members were asked to present their defence during the brief hearing.

CSW said their lawyer, Seyyed Mohammed-Ali Dadkhah, only had time to draft a hastily written statement declaring that their meeting was a religious gathering, that there had been no violation of Shari'a law or the constitution, and reminding the court of constitutional provisions for the rights of Christians and minorities. The group was told to expect an answer from the court within ten days.

The organisation has also learnt that three Christians, Sonia Keshish Avanessian, Arash Kermanjani and his wife Arezo Teimouri, were released from Hamadan prison in late April after being held for nearly eight months without charge.

A fourth member of the group, Vahik Abrahamian, Sonia’s husband, who also has Dutch citizenship, is still behind bars.

They were arrested along with eight others during a Christian meeting at Vahik and Sonia's home and held in solitary confinement in an unknown location for forty days before being transferred to Hamadan Public Prison.

No official charges were made against them during their detention, but in a TV news broadcast last September, they were accused of attempting to destroy the Islamic Republic of Iran, and were referred to as "Zionist Christians".

CSW sources report that the equivalent of £116,000 was demanded for the release of each individual, possibly because the group was known to have links to international Christian organisations.

The three were released when it became clear that such payments would not be made, although their release does not amount to an acquittal.

There has been no explanation given for Vahik Abrahamian’s continued imprisonment.

CSW’s Advocacy Director Andrew Johnston said that a guilty verdict against the Church of Iran members would effectively criminalise the taking of Communion.

It would also constitute a violation of Iran’s pledge under the International Covenant on Civil and Political Rights to respect the right of citizens to manifest their religion or belief in worship, observance, practice and teaching, he said.

Mr Johnston condemned as "wholly unacceptable" the extended detention without charge of the Hamadan group, the demand for sums of money for their release, and the continuing detention of Vahik Abrahamian.

He said: "CSW urges the government of Iran to ensure an end to extended detentions without charge, and that Mr Abrahamian and other members of religious minorities receive due process, are acquitted of all charges that have no legal basis, and enjoy the rights and privileges due to them under the national constitution and international statues to which Iran is party."