Professor Geoffrey Alderman is to lodge a formal protest against Queen's University, Belfast after the withdrawal of an invitation to be a speaker at a Middle East debate on Monday night.

The staunchly pro-Israel JC columnist and historian, who is a guest professor at Ariel College on Israel's West Bank, had been invited to join the panel at a discussion on "Conflict in the Middle East" as part of the Belfast Festival.

But last Friday festival director Graeme Farrow told Professor Alderman that the invitation had been a "mistake" as he had not consulted the other panellists about it.

They were Professor Avi Shlaim, of Oxford University, a leading academic critic of Israeli policy, and Professor Beverley Milton-Edwards of Queen's, the author of several books on the Middle East including a recent study of Hamas.

Professor Alderman, who called the organiser's decision "outrageous", will complain to the Quality Assurance Agency - which monitors academic standards - and the Arts Council of Northern Ireland, which partly funds the festival.

"I believe a strong case can be made that Queen's University has breached its mission statement in promoting diversity and freedom of political opinion," he said.

Professor Alderman, who travelled to Belfast, voiced his unhappiness in meetings with Mr Farrow and later civil servants in the Northern Ireland government. He rejected an offer to join the audience for the debate and ask a question from the floor.

Professor Alderman also met Professor Shlaim. "He said that he and Professor Milton-Edwards had recently published books on aspects of the Middle East conflict and it was only on that basis they were appearing on the panel," Professor Alderman said.

Queen's University vice-chancellor Peter Gregson noted that Professor Alderman had been offered a ticket to attend the debate and it was a matter for him "as to whether he participates".

Mr Farrow explained that the event had sold out on the basis of publicity in August advertising the appearance of Professors Shlaim and Milton-Edwards. But after being approached by Northern Ireland Friends of Israel, he had invited Professor Alderman last month.

"I made a mistake," he said. "I didn't consult the people I'd [already] invited. They thought the event should proceed as originally advertised."

Professor Shlaim said that he had not heard of the invitation to Professor Alderman "until the day of the event".

He added: "I did not invite or disinvite anyone or make any changes to exclude anybody. I like and respect Geoffrey and we had tea in our hotel before the event... As far as I am concerned,
I went ahead with the event as planned, as agreed and as advertised, and I don't have anything to do with controversy that has come to surround it."

Steven Jaffe, of Northern Ireland Friends of Israel, who attended the debate, said the group was "very disappointed that the event was allowed to be so one-sided.

"The organisers were aware of its unbalanced nature and that is why they agreed to bring Geoffrey onto the panel when we raised the matter with them. To then disinvite him undermines the university's commitment to inclusivity and balance which is a key principle of the festival at Queen's."

He added: "Avi Shlaim claimed from the platform that it was inappropriate to invite Geoffrey because the event wasn't about Israel but about conflict in the Middle East generally. In fact, the discussion was almost exclusively about the Arab-Israel dispute."

Professor Milton-Edwards was unavailable for comment. But Zachary Esterson, a postgraduate student in Cardiff, who rang her after hearing about the cancelled invitation, said that Professor Milton-Edwards told him that her family had been threatened.