A Durham college head has apologised for calling students “pathetic” as the university launches an investigation into the events.

       Professor Tim Luckhurst, principal of South College, said he was “wrong” to have criticised a student walk-out during a formal dinner in protest at the guest invitation to the columnist Rod Liddle.

       In an email to members of the College, he said that students had “exercised their right to leave the College Formal” before his guest rose to speak.

       He added that the students had “as much right to absent themselves from the speech as my guest had to make it”.

       Prof Luckhurst’s apology came as Durham University announced it was launching an investigation into the events that took place during the evening “as a matter of urgency”.

       The university said it “categorically” does not agree with the comments made by Liddle during his after dinner speech on Friday night.

       As Liddle rose to speak, several students staged a walk-out from the formal dinner, at which point Prof Luckhurst shouted “at South College, we value freedom of speech” and “pathetic”, according to the student newspaper Palatinate.

       During his speech, Liddle said he was disappointed to not see any sex workers that night, in reference to recent controversy over safety training provided by Durham University to student sex workers.

       He went on to say that the “science or pure facts” are that “a person with an X and a Y chromosome, that has a long, dangling penis, is scientifically a man, and that is pretty much, scientifically, the end of the story”, Palatinate reported.

       “It is fairly easily proven that colonialism is not remotely the major cause of Africa’s problems, just as it is very easy to prove that the educational underachievement of British people of Caribbean descent or African Americans is nothing to do with institutional or structural racism,” Liddle added.

       He finished the speech with a message about the importance of listening to and doubting people’s opinions.

       The university issued a statement saying it is “concerned at reports that the behaviours exhibited at the occasion fall short of those that we expect”.

       It added: “The exchange of ideas within the University should at all times be conducted in a tolerant manner. Everybody has the right to live, work and study in a respectful environment.”

       'South College is committed to the defence of free speech'

       A university spokesman refused to rule out the possibility Prof Luckhurst’s behaviour on the night would form part of the investigation.

       In an email to students sent on Sunday afternoon, Prof Luckhurst said: “I responded to their decision by reminding the students that South College is committed to the defence of free speech. When they did not return to their seats, I called their walkout 'pathetic'.

       “My anger reflected my sincere commitment to freedom of speech. However, I was wrong to describe the students' action as pathetic and I apologise unreservedly for doing so.”

       A Durham University spokesman said: “Durham University upholds freedom of speech within the law. As such we welcome diversity of opinions from our students, staff and visitors.

       “Protection of the right to free speech extends to discussion of issues that are controversial, including the expression of views which may shock, disturb, or offend others.”