Professor Lawrence Krauss, an adviser to U.S. President Barack Obama's 2008 presidential campaign, said the audience was broken into three groups -- males, females and couples. He said a woman who went to the event told him she held hands with a male friend, pretending they were a couple so they could sit together, The Daily Telegraph reported.
The event, "Islam or Atheism: Which Makes More Sense?," was organized by the Islamic Education and Research Academy, which has been banned from conducting events on campus, university officials said.
Krauss said he threatened to leave the event unless organizers agreed to let men and women sit together. He said organizers eventually agreed to the demand, but audience members accused him of intolerance.
Krauss said no such problems occurred when he participated in a similar debate in Australia.
He suggested Britons may be too polite to object to such practices and may be intimidated by those who protest when they believe "their cultural norms are not being met."
"People are not only afraid to offend, but afraid to offend a vocal and aggressive group of people," Krauss said. "There is a segment of the Islamic community that is very vocal about this."
When a woman who spoke during the debate said she wasn't comfortable sitting among men, Krauss said he told her he respected her feelings but added, "You are in a public arena and not in a mosque, not in a private event."
"The notion that because these cultural norms make some people feel uncomfortable in broader society, that broader society should accommodate that discomfort, is complete nonsense," Krauss told the Telegraph.
The organization said the segregated seating at the event wasn't enforced, and it has begun a "thorough internal investigation" into what happened.