The mass shooting at two mosques in Christchurch, New Zealand, which has killed at least 49 people, adds to the grim list of far-right terror attacks that have been increasing over recent years across the globe. Yet, the threat from right-wing terrorism remains blindingly absent from much public discourse on extremism. The atrocity demonstrates what scholars and many of those involved in counter-extremism have been saying for some time: the threat of far-right extremism is a very real one, which poses as big a challenge to civil society as Islamist extremism.

From what we know of the 28-year-old attacker from Australia, Brenton Tarrant, he appears to reflect a standard member of the online far-right community. In a 74-page document entitled "The Great Replacement", he describes himself as an "ethno nationalist" and makes the usual far-right ideological rantings, notably the conspiracy theory that there is a deliberate plot to replace white Christian civilisation populations with ethnic minorities, notably Muslims. His choice of victims tells us everything we need to know about the salience of anti-Muslim prejudice in far right circles.

His own words can only tell us so much and should be taken with a pinch of salt, however. Much of it is written in an ironic style derivative of online alt-right culture, which, as Robert Evans of Bellingcat has already identified, reflects the practice of "shitposting", or, "the act of throwing out huge amounts of content, most of it ironic, low-quality trolling, for the purpose of provoking an emotional reaction in less Internet-savvy viewers". We are better able to understand the motivations of Tarrant from previous attacks, many of which he speaks highly of in the manifesto.

Far-right terrorism and the style of attack witnessed in Christchurch are by no means new but is becoming increasingly common and with a higher casualty list. In one of the most high profile and deadly attacks to date, Timothy McVeigh killed 168 people 24 years ago in the Oklahoma City bombing, while four years later in 1999, Neo-Nazi David Copeland killed three and injured scores in a series of nail bomb attacks in London. More recently, we have seen high profile cases such as Dylan Roof’s mass shooting on a predominantly black church in Charleston, South Carolina in 2015, while last year saw 11 killed by an anti-Semitic white nationalist shooter at a Synagogue in Pittsburgh. The media is often quick to associate far-right terror attacks with mental illness, and mental health is surely an important question in terms of radicalisation, yet all attacks are motivated by a similar ideology – the belief in white supremacism and conspiracy theories which allege sinister plans designed to eradicate the white race.

Terrorism is the most extreme tactic of the far right, who have, over the past three decades demonstrated that their ideas (if astutely presented) can achieve electoral success. The aim of terrorism is, of course, to target and kill outgroups despised by the far right and blamed for the alleged degeneration of western “white” civilisation. Yet, their aims are increasingly about publicity and glorifying racist violence on the internet and social media. They seek to recruit others to the cause by proclaiming themselves, previous attackers and by extension future terrorists as martyrs. Tarrant filmed his attack not just for the world to see, but to radicalise others and encourage them to continue in his footsteps. He has encouraged others to: "make your plans, get training, form alliances, get equipped and then act".

Tarrant clearly took great inspiration from one of the most notorious far-right attacks which came in 2011, when Anders Breivik murdered 77 (mostly children) in Norway. Breivik’s attack appears most similar to Tarrant’s murder both in terms of weaponry and scale. Writings produced by Breivik and Tarrant are similar in terms of content – which is a mix of white nationalist and Islamophobic slogans, myths and conspiracy theories. In addition to the suffering and casualties caused by the attack itself, far-right terrorist attacks can and indeed seek to influence others. As Tarrant’s document claims: "I support many of those that take a stand against ethnic and cultural genocide [...] Anders Breivik, Dylan Roof". This will not be the last far-right terror attack and without doubt, many who share Tarrant’s worldview will be inspired and encouraged to conduct similar attacks.

Yet, we cannot look to the small, dispersed white nationalist community alone to understand their actions. The far right more broadly have become emboldened in recent years by global events and mainstream responses. Islamist terror attacks in France, Britain and the United States and the sensationalist reporting which has followed them in the media - have fed into their narrative of a clash between Muslim and Christian civilisations.

The victories of far-right populists in Europe, the election of Donald Trump as well as Brexit – all of which have weaponised Islamophobia in order to achieve success – have all contributed to the far right’s perception that they live in an age of great opportunity for their movement. The far right ultimately crave the oxygen of publicity as a route to respectability, something which has been handed to them on a plate by influential mainstream commentators and politicians who regularly repeat racist and Islamophobic tropes.

Extremists like Tarrant and countless others have been emboldened not just by an online community of the like-minded, but by a much wider pool. It is crucial that when the shock over the senseless murder of (at least) 49 innocents dies down, we focus on both the immediate threat as well calling out those who provide ideological ammunition and succour to violent terrorists.

Dr Paul Stocker is a Senior Fellow at the Centre for Analysis of the Radical Right and a Visiting Fellow at the University of Northampton. He is author of English Uprising: Brexit and the Mainstreaming of the Far Right.