Some of the world’s leading scholars on China have called for a united international front in defence of university freedoms, amid claims of an increased Chinese threat to academic inquiry since the passing of Hong Kong’s national security law.

Individual universities will be picked off unless there is a common agreement to resist Chinese state interference in academic research and teaching on China, a group of 100 academics including scholars in the US, UK, Australia and Germany say.

They highlight the threat posed by article 38 of the sweeping national security law, which states that the law is applicable to individuals who live outside the territory and individuals who do not come from there.

The law was imposed on Hong Kong by Beijing in June after more than a year of pro-democracy protests.

The academics say article 38 raises the unsettling prospect that students travelling through Hong Kong and China face being handed lengthy prison sentences on the basis of academic work deemed to be subversive by Chinese authorities.

The signatories, representing 71 academic institutions across 16 countries, cite claims that China-related modules are being dropped and writings self-censored by students for fear of reprisals.

“Universities are supposed to be a place for vigorous debate, and to offer a safe space for staff and students to discuss contentious issues without fear or favour,” says a letter signed by the academics. “The national security law, which under article 38 is global in its scope and application, will compromise freedom of speech and academic autonomy, creating a chilling effect and encouraging critics of the Chinese party-state to self-censor.”

Dr Andreas Fulda, a senior fellow at the University of Nottingham Asia Research Institute and one of the initiators of the letter, said: “Several students – both from the United Kingdom and from mainland China – have told me in private that they are concerned that comments made in class or essays will be used as evidence against them.

“Universities cannot meet this challenge alone. A united front of academic leaders, politicians and senior government officials is needed to mount a common defence of our academic freedoms. We must call out the national security law for what it is: a heavy-handed attempt to shut down critical discussion of China, antithetical to the pursuit of knowledge and understanding.

He added: “It is widely known that the Chinese party-state is weaponising students to monitor their university instructors in mainland China and Hong Kong. Such attempts to instrumentalise students do not stop at China’s border. Prof Vanessa Frangville has revealed that the Chinese embassy in Brussels tried to hire Brussels campus students to express their disapproval of a Uighur demonstration in 2018.”

A lecturer in Sinology at the University of Leipzig recently told the Hong Kong activist Glacier Kwong that “his students from Hong Kong, Taiwan and China asked if they could drop his class, because they worried about being associated with the criticism others made of the Chinese Communist party in class”.

A separate group of British academics have this week called for a code of conduct so that higher education teachers are consulted at all stages over how collaborations between universities and foreign governments are administered.

The code calls for US-style transparency on the overseas funding of universities, and a national ombudsman to whom breaches of the code can be referred. They also want greater protection for foreign students on campus and for UK researchers working in authoritarian states.

The code is expected to be supported in principle by a Universities UK paper due to be published this week that will also cover issues such as the protection of intellectual property on campus.

Individual Chinese professors at Oxford University have said they intend to anonymise some student papers given in group settings in an effort to reduce the perceived fear of reprisals for discussing flaws in the Chinese model.

John Heathershaw, a professor of international relations at Exeter University, said: “The open market model of university funding risks leaving individual universities vulnerable to approaches by authoritarian donors, and there needs to be much greater transparency and involvement of the faculty at an early stage about the terms on which grants are given.”