But rather than jump to his defence, or even just ignore the online abuse he faced, he was astonished to see his “left-wing” colleagues join in.
Sue Bond-Taylor, another Lincoln University lecturer in social policy, contacted the abuser on Twitter and urged him not to “discount the whole team off the back of the work of one member of staff”.
Meanwhile Dr Dunn felt that Liam McCann, now the acting deputy head of Lincoln’s school of social and political sciences, appeared to “sneer” at him and question why his work was worthy of funding.
“Insults, swearing and rudeness are commonplace on Twitter, but what happened involving [my colleagues] shocked me as I have never seen anyone behave in such a rude and disrespectful way towards a word colleague in view of the public on a social media site,” Dr Dunn told the tribunal.
He complained about the incident to his line manager and the university launched an inquiry which found that Dr Dunn, along with his colleagues, had all breached the institution’s “respect” policies.
He said that by finding him equally at fault with his colleagues “the inescapable conclusion” is that he had been discriminated against due to his “political philosophical beliefs”.
Over the next two years he had several other disputes over social policy with academic colleagues and students, he was eventually dismissed in August 2017.
Dr Dunn’s claim that he was discriminated against for his anti-PC beliefs was thrown out by the Judge Blackwell last month, who ruled that: “The belief that the tendency to favour what is palatable in social policy discussions over the truth (in colloquial terms this tendency is known as political correctness) is not a philosophical belief that has the protection of section 10 of the Equality Act 2010.” A Lincoln University spokesman said: “The claims by a former employee made in this case were dismissed by a tribunal panel. We welcome diversity of opinion and debate on our campus while treating staff, students and visitors with dignity and respect.”