Prof Gilley said he was “disappointed and surprised that the backbone of academic freedom seems to be weakening in Oxford” A spokesman for Oxford University said: “We are wholly committed to freedom of speech and encourage our students to debate and engage with a wide range of viewpoints.“The decision to hold the event in private was taken by the academic to avoid the risk of disruption, and a notice of the event was published online afterwards.”A “controversial ideas” journal where researchers can publish articles under pseudonyms will be launched next year by an Oxford University academic.Jeff McMahan, a professor of moral philosophy at Oxford, said the new journal is a response to a rise in researchers being criticised and silenced by those who disagree with them. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. Academics launched a vociferous attack on him last year after he suggested that people should have “pride” about aspects of their imperialist past.He said that the history of the British Empire was “morally mixed” and that “just like that of any nation state, then pride can temper shame”. Over 50 professors, lecturers and researchers signed an open letter expressing their “firm rejection” of his views. Prof Gilley, who attended event in May, said he understood why the event was held in private, as “there is no point creating a spectacle, we wanted to have a substantive discussion”.He told The Daily Telegraph: “Seeing Nigel close the door – it felt medieval, as though we were monks during the dark ages.”You always think as you walk into a conference room or a seminar room, ‘I hope lots of people come’. You always have an inclination towards openness. Holding the event in secret struck me as the most bizarre experience I ever had.”Referring to the chorus of disapproval from fellow academics about the Ethics and the Empire project, he said: “I was disappointed and surprised that the backbone of academic freedom seems to be weakening in Oxford”. An Oxford University professor had to hold an academic conference in private for fear of disruption from activists, it has emerged.Earlier this year, Professor Nigel Biggar hosted a summit of historians, economists and ethicists to discuss the legacy of colonialism, but the invitation-only event took place behind closed doors.The event was aimed at reflecting on the American political science professor Bruce GiIley’s controversial article, titled “The Case for Colonialism”, which argues that colonial rule was sometimes legitimate and that post-colonial states would do better to nurture certain aspects of their colonial legacy than discard them.Prof Biggar said that he often holds such meetings in private because “the quality of discussion is better with a small, hand-picked group”. He said: “But on this occasion [it was] also because I didn’t want to risk activist disruption.”–– ADVERTISEMENT ––He explained that another reason for holding the event in private was that one young scholar would only attend on condition of anonymity, “lest his attendance come to the attention of some of his senior colleagues and “count it against his career”.Prof Biggar, who is head of the McDonald Centre for Theology, Ethics, and Public Life, is currently leading a project on “Ethics and the Empire”, which analyses the impact of Britain’s imperial past.