Following the referendum result, leave campaigners gave assurances that a post-Brexit Britain would remain “open to the world”. Instead, we have witnessed increasing signs over the last few days of a Powellite drift towards insular nationalism, with UK universities as easy targets. We have seen proposals for restrictions on the number of overseas students and for organisations to be forced to reveal the proportion of their workforce which is “foreign”. And most recently (Foreign experts are excluded from advising UK on Brexit, 8 October) evidence has emerged that UK-based academics will be excluded from consultations with government on particular issues if they are not British citizens.

For centuries, scholars have considered themselves part of an international community of learning. Universities have thrived when – like British institutions in recent years – they have been able to play a full part in this international exchange of ideas and people. But when, for ideological reasons, governments have sought to isolate them, they have stagnated, and with them the intellectual and creative life of the societies they served. This will be Britain’s fate unless we defend the outward-looking nature of our universities, and the rights and dignity of all academics in this country. It might be naive to hope that the undertaking to maintain the UK’s engagement with the rest of the world will be honoured. But it would be nice to think that not all the promises of the Brexiteers were outright lies.

Professor Philip Murphy

Director, Institute of Commonwealth Studies

• In attacking world citizenship in her dictum, “If you believe you are a citizen of the world, you’re a citizen of nowhere”, Theresa May is in effect repudiating Enlightenment values as a whole, for cosmopolitanism is the apex and indeed the glory of Enlightenment philosophy, encompassing liberty, equality, fraternity, and all our human rights. The greatest of all Enlightenment thinkers, Immanuel Kant, proposed the ideal of world citizenship as a means to achieve perpetual peace. In the 20th century, his views underwrote the founding of the United Nations, an organisation which invokes world citizenship as a means to attain world peace. The very different, pejorative sense of cosmopolitanism adopted by Ms May, however, originates in German antisemitic discourse. It emerged in the 19th century: the “rootless Jew” was seen as a “cosmopolitan” citizen from “nowhere”. This view is echoed in that most vile of all antisemitic texts, The Protocols of the Elders of Zion (1903). Subsequently, the prejudice was adopted by the Nazis, and used to justify the slaughter of the Jewish people as “non-citizens” and “non-persons” in the Holocaust. Is that where our xenophobic PM wants to lead us, this time by scapegoating “foreigners”? I don’t appear to be the only one who senses echoes of 1933 in our brave new Britain.

Jeremy Adler

King’s College London

• Theresa May’s assertion of the need to tax “citizens of the world and of nowhere”, presumably referring to foreign investors in the UK, may have been “felicitous” as Simon Jenkins says (May has the party’s adoration for now. That won’t last, 6 October). Curiously, however, a Google search (deleting the second “of”) suggests that the phrase originated as an epithet for the Roma people, albeit not intrinsically a pejorative one. It also bears a striking similarity to the more sinister term “rootless cosmopolitans”, deployed by Stalin to justify his late 1940s purge of Jewish intellectuals. One can only hope that these connections are indicative merely of a cloth-eared speechwriter, rather than of a dog-whistle aimed at the sharp ears of the racists who are already walking tall in Brexit Britain.

Rob Sykes

Oxford

• As a British citizen living and working in Europe, I have long kept my faith that the rise of rightwing, xenophobic populism will ultimately be checked by democratic forces. Following a conference in which the Conservatives seem hellbent on driving an alarmingly reactionary agenda into the heart of British society, I am not so sure. I can only hope that a majority of the British public will remind this political elite that it does not share such shoddy values. Brexit or no Brexit, this is not the sort of leadership any self-respecting country should tolerate in times like these.

Ben Horsbrugh

Oldenburg, Germany