You don’t have to be an open-borders fanatic to want writers and others to be able to cross frontiers to exchange views with like-minded people abroad. Unfortunately, this is not the view of the UK Home Office, which increasingly prefers to keep out anyone whose views offend the progressive establishment.

Since last year, anyone seeking to visit the UK visa-free has had to get an Electronic Travel Authorisation (ETA). A consequence is that apparatchiks can now keep out anyone officialdom disapproves of at the click of a mouse.

Home Office officials have relished their new powers. Polish MEP Dominik Tarczyński, who wanted to attend the first Unite the Kingdom rally, was banned from entering the UK in May. Two critics of Israel who had been invited to speak at the Oxford Union, Hasan Piker and Cenk Uygur, were denied in June. Dutch right-wing lawyer and anti-immigration activist Eva Vlaardingerbroek had her ETA rejected in January. Most recently, the Christian Finnish parliamentarian Päivi Räsänen was prevented from addressing a conference in Northern Ireland on religious freedom when her ETA was pulled at the last minute, apparently owing to a conviction in Finland over a pamphlet attacking homosexuality she had written more than 20 years ago.

This isn’t exactly new. Senior members of the Westboro Baptist Church, which notoriously claims that God hates gays, have been excluded for some time. So too have a few inflammatory critics of Islam like Robert Spencer (and, to be fair, have many Islamist fanatics as well). In 2018, three prominent anti-Islam activists were denied entry to the UK.

This is very worrying. True, we must always have the right to control who comes to the UK. And we must be able to take into account what they might say if admitted. There is nothing immoral about shutting out the loud-mouthed Islamist bigot who publicly demands the end of democracy, and the subjection of everyone to some dark Sharia code. Equally, while free speech means our police must, however awkwardly, hold the ring between our own home-grown firebrands and their opponents, this does not mean we must admit any foreign rabble-rousers who want to come here and make their life even more difficult.

But that’s not really what’s going on her. Attending a demo is not the same as whipping up a frenzied mob of rioters. Speaking at the Oxford Union is hardly dangerous rabble-rousing. And it’s hard to see any harm whatsoever in allowing a venerable Finnish politician to address an obscure Northern Irish conference on religious liberty. It’s hard to avoid concluding that the Home Office has simply decided that its job description includes policing the opinions that can be heard in Britain, with a particular focus on any views that offend the lanyard class.

If the aim of these visa bans is to prevent such views gaining ground in Britain, then it’s not going to work. After all, even if a speech can’t be given in Britain, the internet means it can still be made to Britain. Indeed, trying to stop views being expressed here by publicly keeping out the person wanting to express them almost certainly gives them much more publicity than they otherwise would have got.

More to the point, it sets a dreadful example for free speech. If we believe in the free flow of intellectual discussion, there is something very odd in saying the same speech can be given at the Oxford Union by a British citizen but not a foreign commentator, or that a religious meeting should be prevented from hearing a particular view on sexual ethics if delivered by a Finn, but allowed to hear it from a Brit.

In short, it should not be the role of immigration officials to decide which temporary visitors’ views are acceptable and which aren’t. Those who come may be scumbags with views that make people sick. So be it. Let them come and speak. If you don’t like what they say, the answer is to shout it from the rooftops, not to create some genteel cordon sanitaire and enforce it with the power of the state.

Andrew Tettenborn is a professor of commercial law and a former Cambridge admissions officer.