What happened to no platform? The idea that certain viewpoints had no right to be expressed in public debate has never been wholly uncontroversial, but at least it used to be clear: as Nick Lowles of the anti-racism campaign Hope Not Hate explained it in a 2013 blog post, no platform was “the position where we [ie anti-fascist groups] refuse to allow fascists an opportunity to act like normal political parties […] which sometimes includes physically deny[ing] them the freedom to operate.”

No platform might be enacted in a number of ways: it could mean an institution refusing to host speakers associated with particular violent groups (something the NUS has historically done), or established political parties forbidding their representatives to share the stage with figures from far-right organisation. As a last resort, it meant taking direct action to prevent the proponent of an abhorred position from speaking. But it was traditionally about rejecting the rhetoric of violence – especially when that rhetoric was liable to inspire leagues of smash-happy skinheads.

Now, no platform's remit appears to be broader. Witness the recent video from a debate at Galway University, where writer and editor Alan Johnson attempted to make the case against a boycott of Israel. Johnson’s speech is barely audible above the noise of the crowd, who boo and drum the desks. The loudest opponent, dressed in the colours of the Palestinian flag, shouts: “Fucking Zionist fucking pricks […] Get the fuck off our campus.”

What’s at stake here isn’t the issue of right and wrong in Middle East politics, and your feelings on Johnson’s treatment shouldn’t be determined by whether you personally back sanctions against Israel or not (an issue on which even avowed opponents of Israeli policy might have good-faith disagreements, after all). His motion went unheard because there was an element of the audience that considered whatever he had to say to be unsayable. Not merely false, not something to be robustly opposed, but a position so appalling it simply shouldn’t be heard.

What’s truly remarkable is that while this is happening, no platform has been more or less abandoned by the anti-fascist movement. That wasn’t because of a sudden conversion to the benefits of free speech, and it wasn’t even close to to universally welcomed, but it was probably inevitable. There are two reasons for this, one political and one technical. Firstly, British far-right and anti-immigration parties started to enjoy electoral success in the early 21st century, making it difficult to justify refusing them a platform: once BNP leader Nick Griffin became Nick Griffin MEP, the case for keeping him off Question Time became at the very least tenuous.

Secondly, blogging and social media meant that a platform was no longer something that could be withheld: anyone with any views can now hold forth so long as they have an internet connection and a Twitter login. For Hope Not Hate’s Lowles, no platform has to be reinvented, from a policy of radical non-engagement to one of equally radical popular engagement by which campaigners can “deny fascists, organised racists and other haters the freedom to spread their poison within communities unchallenged.”

Whether that will be sufficient intervention to stem the necrotic spread of British racism is uncertain, and the aftermath of Griffin’s 2009 Question Time appearance offers ambivalent lessons. After a fleeting and insignificant bump in the polls, it seemed that cheerleaders for the power of scrutiny would be vindicated: Griffin’s twitchy, evasive performance was seen as a disaster within the BNP, and exacerbated the divisions that led to the party’s collapse, explains Daniel Trilling, author of Bloody Nasty People: The Rise of Britain’s Far Right.

But long term, the outcome was less wholesome. “It contributed to the shifting rightwards of the debate on immigration,” says Trilling. We live in the era of the Go Home Van, in a time when less-than-alarmist reports on the effects of immigration are deemed so politically sensitive they have to be suppressed. Even if Griffin lost Question Time, we can’t pretend that anti-racism won the war.

It’s arguable that no platform must have failed long before 2009 for the BNP to have any electoral success, and yet there are still groups who aggressively advocate the strategy. There’s a difference, however. The no platform of now doesn’t target groups such as the National Front or the EDL – instead, it’s aimed at individuals who certainly do not trail the organised muscle of a thug army behind them. One of these individuals is the feminist journalist and campaigner Julie Bindel, who has been repeatedly no platformed because of a 2004 Guardian column in which she made facetious criticisms of gender reassignment surgery and transsexual activists that many people found offensive. She’s since apologised for both the tone and the content of the column, she tells me during a phone interview, but that hasn’t placated her opponents.

“I have to pay for the rest of my life because of a very small group of trans women,” she says. “I haven’t said anything hateful to any of these people, ever. All I have ever said was question the essentialist meaning of transgenderism, because, by positing gender as fixed it flies in the face of feminism.” Subsequently, Bindel has been prevented from speaking not just about transgender issues, but also about violence against women and girls. The no platforming has taken the form of direct intimidation – “I had death threats […] I was shouted at, physically attacked on stage,” Bindel tells me – as well as coming in more official guises. In 2011, the NUS GLBT conference voted to no platform her, and approved the extraordinary motion “this conference believes Julie Bindel is vile”. (Meanwhile, various tyrants and dictators have been hosted by NUS venues.)

While writing this article, I contacted Roz Kaveney, a trans activist and supporter of the no platform policy against Bindel. (Kaveney is also a founder member of Feminists Against Censorship, making her both an idealogical opponent of Bindel on pornography and an arguably curious advocate for no platform, although she sees no conflict between the two positions.) I ask Kaveney ask why she feels Bindel should be excluded from public debate, and she replies by email: “You would, I trust, accept that such places as universities are supposed to be safe spaces that have a duty of care to their students. Hate speech is, almost by definition, something which cannot be allowed in a safe space.”

However, when I ask Kaveney for some examples of Bindel’s statements which qualify as hate speech, she only says: “I’d be hard put to it to find an area in which Julie Bindel’s discourse does not, sooner or later, descend into hate speech.” But having withdrawn from the email correspondence, Kaveney then begins to tweet about our exchange. “I love the assumption that I have time and energy to list offensive remarks by Julie Bindel & then explain why each one of them is hatespeech,” reads one tweet. Another says: “Remember my past remarks that one aspect of WLF [white liberal feminist] transphobia is the demand for endless unpaid access to trans people’s time? That.”

Kaveney’s comments imply a trans consensus against Bindel, but there are plenty of dissenters. Journalist Jane Fae, who is also trans, disagrees with Kaveney. In an email, Fae (who has herself debated Bindel) says that she is opposed to no platforming, both in this specific case and generally, although she supports the right of individuals to refuse to share a platform. “I can’t see myself agreeing with much of what she [Bindel] has to say,” writes Fae, “but I do not feel intimidated by her.” These are, after all, disagreements about ideas, not personal attacks or acts of violence. The ability to debate competing viewpoints is one of the foundations of democratic society, and as dissent is elevated to the status of offence and then to hate speech, the consequences become alarming.

Intimidation is at the core of no platform – both the arguments for it and, increasingly, its practice. Why should a woman speaking for feminism, or a man speaking for Zionism, be deemed such a threat that they have to be shouted down, condemned as “vile”, or told to “fuck off”? Why, in the new economy of outrage, have people like Bindel and Johnson attracted the opprobrium that was formerly reserved for hypermasculine, anti-semitic white power movements? No platform now uses the pretext of opposing hate speech to justify outrageously dehumanising language, and sets up an ideal of “safe spaces” within which certain individuals can be harassed. A tool that was once intended to protect democracy from undemocratic movements has become a weapon used by the undemocratic against democracy.