OXFORD - Hundreds of protesters disrupted a debate on free speech at Oxford University on Monday, throwing eggs and staging a sit-in to try to prevent convicted Holocaust denier David Irving from speaking.

Riot police ringed the approach to the 184-year-old Oxford Union building in an effort to keep the protests by about 500 anti-fascist demonstrators, including Jewish and Muslim students, as peaceful as possible.

The debate was delayed by an hour-and-a-half but eventually went ahead in altered form with Irving, a British historian convicted and jailed by an Austrian court in 2006 for glorifying Nazism, taking part despite howls of protest.

Irving was due to be joined by Nick Griffin, leader of the far-right British National Party, in the debate with four other speakers, including two students, in the same hall.

But when the protesters broke into the hall and disrupted proceedings, the event became a fractured discussion, with Irving in one room with two other speakers and Griffin in another room with the remaining two.

The demonstrators had gathered outside the prestigious debating society, where former U.S. President Bill Clinton and Mother Theresa have spoken, several hours before the debate.

Irving and Griffin were spirited into the hall before the demonstrations began.

Afterwards, students who took part in the debate said they were glad it had gone ahead despite the disruptions.

"I think it was a very balanced argument and both sides did really well," undergraduate Roland Scarlett told the BBC.

Protesters said they were pleased to have made their point.

EXTREMISM

Commentators had lined up to condemn the union for staging the debate, saying the student-led organisation was giving a platform to extremism partly in an effort to attract attention. The union has previously invited Kermit the Frog to speak.

Enraged at Irving's invitation, several prominent people, including British Defence Secretary Des Browne, cancelled engagements for future debates. A politician from the opposition Conservative Party resigned from life membership of the union.

Irving, 69, has written several books which defend Adolf Hitler and deny the systematic extermination of six million Jews by the Nazis. He has been branded anti-Semitic and a racist by a British judge.

Griffin's party is on the fringe of British politics, earning a reputation for strident positions against Muslims and immigration, although he has denied racism.

Oxford Union President Luke Tryl had defended the decision to invite the two saying the best way to counter extremism was to defeat it intellectually in debate.

"These people are not being given a platform to extol their views but are coming to talk about the limits of free speech," he wrote in a letter to union members who had expressed concern.

"It is my belief that pushing the views of these people underground achieves nothing ... Stopping them speaking only allows them to become free speech martyrs."

Ned Temko, chief political correspondent of the Observer newspaper and a former editor of the Jewish Chronicle, said it was disingenuous of the debating society to invite the two and then try to hide behind the banner of freedom of speech.

"It's not a question about giving them a platform, it's about giving them credibility," he told the BBC. "It's ridiculous and it's irresponsible."