The Cambridge Union Society is embroiled in further controversy this week after a guest speaker walked out of the chamber in the final minutes of the debate on Thursday night.

Stephen Gash, who was speaking in support of the motion "This House believes Islam is a threat to the West", interrupted the final speaker of the opposition, Abdullah Al-Andalusi, on several occasions, as response to Al-Andalusi's alleged personal attacks against him.

After being warned by Union Vice-President Jeremy Schwarz that he risked being removed from the chamber, Gash chose to walk out.

Gash is a former leading member of the pressure group Stop the Islamification of Europe (SIOE). Al-Andalusi is a Muslim community activist and public speaker.

Al-Andalusi told Varsity, "I would like to point out that I made no personal attacks on Stephen Gash, but references to the ideas and beliefs of his organisation, and its members. I am only aware of Stephen's political opinions, and not his personal character.

"I think he [Gash] objected to being reminded that his opinions are similar to those of the BNP in front of such an audience."

According to Al-Andalusi, "I found it upsetting that Mr Gash could not respect my right to speak, as I had done for him. I had not even offered a point of information during his speech."

Explaining his side of the story, Gash said, "I was angry because I was led to believe that proposers and opposers of the motion would refrain from making personal comments on each other. This was not the case and the final speaker opposing the motion associated me with the BNP.

"I have denounced the racism of the BNP on may occasions and continue to do so. I have stood against them several times in elections. However, the rules of the debate forbade me to refute the false accusations against me.

He added, "As I was prevented from responding, I chose to leave. I consider that double standards were applied to my disadvantage. I could have demolished the person concerned in a matter of four sentences, but chose instead to debate the motion."

Speaking to Varsity, Union Head of Press Alex Küng said, "The Cambridge Union impartially upheld its rules throughout the debate. Unfortunately, Mr. Gash chose to walk out because he believed that Mr. Abdullah Al-Andalusi's personal attacks were inexcusable.

"Whether this is true or not misses the main point: that every speaker is afforded an equal share of time to express his/her position freely, within the boundaries of UK law, notwithstanding the contrasting views of those at the debate."

Al-Andalusi appeared to concur with the Union's assessment saying, "My perception is that the Union handled the matter impartially."

Gash, similarly, praised the Union, saying, "I commend the CU for holding the debate and would humbly suggest it continues to hold controversial events. Like beauty, provocation is perceived by the beholder."

The incident comes just two weeks after criticism was levelled at the Union for allowing a student speaker with purportedly pro-Israeli sympathies to argue for the motion "This House Believes that Israel is a Rogue State".

Frustration about the variety of guest speakers invited to the Union this term was further reflected when a signed letter was sent by students to the Union President.

Protesting against the decision to offer a platform to "controversial speakers simply for sensationalism", the letter added, "it appears that these speakers have no credentials for such a debate besides just being simple Islamophobes."

Many students who were in the audience on Thursday also voiced their criticism about the motion itself. One student from Gonville & Caius College commented that the motion had "failed to engage with the differences between Islam and Islamism, leading to an intentionally confrontational and unreflective discussion."

This article was amended and updated at 1900 GMT on Sunday, November 7, 2010.