Across 115 higher education institutions included in the first ever Free Speech University Rankings, produced by the online magazine Spiked, 135 bans were instituted or upheld over the past three years.

Of these, 32 were bans on newspapers imposed by students’ unions – 26 of which involved the Sun and the Daily Star as part of the No More Page 3 campaign.

The controversial Robin Thicke song Blurred Lines, which has faced accusations of sexism, was banned by 21 unions.

Only 23 institutions were given an overall “green” ranking in the rankings – meaning that they did not impose any bans beyond legislative requirements, and did not have any regulations that were judged to chill freedom of expression.

The top performers included the University of Wales Trinity Saint David, the University of Winchester, the University of Buckingham and London Metropolitan University. Alongside them were Liverpool Hope University, the University of Sunderland and Southampton Solent University.

A total of 47 institutions were given a “red” rating and five were named as being particularly censorious. These were the University of Essex, Bath Spa University and the University of Northampton, plus the University of Portsmouth and the University of the West of England.

The study found that in most cases it was students’ unions that were responsible for “red” ratings. Of these, 51 per cent were rated “red”, compared with 9.5 per cent of university administrations.

Among the policies that were perceived as being restrictive were “no platform” rulings, which ban individuals or groups thought to hold far-right or extremist views. These were found in 37 per cent of students’ unions.

Eighteen per cent of unions have “safe space” policies, protecting students from material deemed offensive, and more than two-thirds of these were judged to place significant restrictions on freedom of speech.

Codes of practice designed to uphold free speech were felt by Spiked to actually restrict it in 31 per cent of cases, while for anti-bullying policies the result was 48 per cent.

“If students and academics can’t say the unsayable and think the unthinkable, universities quickly lose their purpose,” said Tom Slater, the coordinator of the rankings. “How can you pursue knowledge if you can’t test all ideas and explore them?”

Pro-Israel and pro-life groups were also targeted by bans – as was a Nietzsche reading group, outlawed by University College London Union on the grounds that it promoted fascism and racism.

chris.havergal@tesglobal.com