The controversy surrounding a reading of the Koran at a Christian cathedral has deepened after it emerged the text read included a passage that explicitly declares Jesus is not the Son of God.

The denial of this key Christian doctrine was read out at a leading cathedral of the Scottish Episcopal Church in Glasgow.

The cathedral's Provost, Rev Kelvin Holdsworth, invited the recitation from the Islamic holy book that gave the Muslim interpretation of Jesus' miraculous conception and birth. The reading was given by Madinah Javed, a Muslim law student, at St Mary's Cathedral at the Epiphany service which celebrates the incarnation of God as His son Jesus.

Christian Today initially reported the reading before it became apparent the denial of Jesus' divinity was also read. It has since emerged that Javed went beyond her allocated text to include the controversial verse.

In a Facebook post shortly after the January 6, the Cathedral described the service as a "wonderful event".

It says: "The congregation was also reminded during the service that it is not only Christians who give honour to Jesus. We were joined by friends from two local Muslim communities." The post also shares a video of the recitation.

But Javed went beyond the allocated text in the service sheet to include a passage that outrightly denied Jesus was God's son, a key Christian doctrine.

The initial verses translated in the service sheet do not include the controversial passage that provides one of the crucial differences between Islam and Christianity.

Javed, reciting in Arabic, went beyond the set reading to the following passage which states: "It is not befitting for Allah [God] to take a son."

It is not clear whether the cathedral knew Javed's reading would include the controversial passage or whether she read it without permission.

Holdsworth was unavailable to comment and a Cathedral spokesman declined to offer a response.

Madinah Javed has also been contacted for comment.

Rev Peter Ould, a conservative Anglican from Canterbury, wrote in a blog post: "It's one thing to share examples of Muslim scriptures in a non divine service context, it's another to specifically incorporate them into Anglican liturgy."

Michael Nazir-Ali, a leading evangelical Christian in Britain, has condemned the reading last Friday.

"The authorities of the Scottish Episcopal Church should immediately repudiate this ill-advised invitation," he said in a statement.

He also called for the Archbishop of Canterbury, Justin Welby, to publicly distance the Church of England and the wider Anglican Communion from the event.

"Christians should know what their fellow citizens believe and this can include reading the Qur'an for themselves, whether in the original or in translation. This is not, however, the same thing as having it read in Church in the context of public worship," he said.

"It is particularly insensitive to have this passage read in Church on the Feast of the Epiphany when we celebrate not only Christ's manifestation to the gentiles but also his baptism and the divine declaration, 'you are my beloved son in whom I am well pleased'."

The Scottish Episcopal Church refused to comment.