The suspected Christchurch mosque shooter claimed he was just one of “millions” of people holding the beliefs that inspired the massacre of 49 people.

Brenton Tarrant said only Anders Breivik’s Knights Templar group knew of his plan but said he had “donated to many nationalist groups and interacted with many more”.

He claimed he decided to carry out an attack two years ago, while on holiday travelling in western Europe in early 2017.

Security sources have told The Independent Tarrant may have met extreme right-wing organisations during his visit, which coincided with increased tensions over Isis-inspired terror attacks and the French presidential election.

His “manifesto” was posted to messaging board 8chan with a plea for anonymous users to spread his message around the world, and they did.

But nothing in the 16,000-word document is new – the ideas, ideologies and memes used have long been spread by far-right groups and figures across the US, UK, Australia and Europe.

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Tarrant has also expressed his belief in the white genocide conspiracy theory, which states that white people are being “replaced” by non-whites in western nations.

He used the so-called 14 words at the core of the theory in his manifesto.

The phrase – “we must secure the existence of our people and a future for white children” – has been appropriated by far-right terrorists around the world, including the UK’s National Action neo-Nazi group.

Other proponents of the white genocide conspiracy theory include former journalist Katie Hopkins, InfoWars’ Alex Jones and Canadian YouTuber Lauren Southern.

Donald Trump drew attention to the theory in 2016, when he retweeted a post by a racist and antisemitic account called “WhiteGenocideTM”.

An alternative version of the same theory, called “the great replacement”, is spread by the pan-European ethno-nationalist group Generation Identity and it was chosen by Tarrant as the title of his document.

Generation Identity’s UK chapter started in 2017 and has been sending members to indoctrination camps in France, while carrying out incendiary publicity stunts at universities and protests.

Its real-life membership in Britain is small, but it has been amplified online by figures including anti-Islam activist Tommy Robinson.

Its members were seen waving banners at a recent pro-Robinson protest in Manchester and leafleting at the Brexit “betrayal” march led by Robinson and Ukip through London in December.

Before its main account was banned on Twitter, Generation Identity would frequently post unverified statistics and claims about the “replacement” of white people in British towns and cities, and declining birthrates.

Demographic change in Europe and debate about how migrants should be integrated has been seized on by the far right and driven a surge in support for populist parties in recent years.

Many extremist groups use birth rate statistics to claim white people are threatened in the continent, but “white” ethnicity is ill-defined.

Research suggests higher birth rates are linked to cultural and socioeconomic factors in new migrant families, and converge with the local population over time.

There is zero evidence that white people are on course for extinction, nor that anything that would even approximate a coordinated attempt to supplant (let alone kill) them is under way.

Anders Breivik massacred 77 people in 2011 (AFP/Getty) (AFP/Getty Images)

The claims were a recurrent theme of Tarrant’s screed, which called for white people to kill non-white and Muslim “invaders” and have more children.

Tarrant claimed he had “brief contact” with Breivik, whose own manifesto has inspired attackers and plotters including a US coast guard officer who plotted to kill Democrats and journalists.

He claimed he then told Breivik’s followers, who call themselves the Knights Templar, of his planned attack and received their “blessing”.

It is unclear whether contact between Tarrant and Breivik would have been possible. Norwegian authorities have said the computer the mass murderer is allowed has no internet access, and phone conversations are allowed only with a “female friend”.

He is permitted some correspondence but letters are controlled, specifically to prevent communication with other right-wing extremists.

Breivik massacred 77 people in the 2011 attacks targeting the Norwegian government and young Labour Party members.

Other inspirations cited by Tarrant include the British Union of Fascists leader Oswald Mosley and far-right terrorists including Finsbury Park attacker Darren Osborne, Sweden school attacker Anton Lundin Pettersson, Italy migrant shooter Luca Traini and Charleston church shooter Dylann Roof.

Tarrant denied being a Nazi but called himself a “fascist” and used neo-Nazi motifs including the Odin Cross and “black sun”, which was featured on the front page of his manifesto.

The document was mainly formatted as a bizarre Q&A, where he asked himself: “From where did you receive/research/develop your beliefs?”

The reply read: “The internet, of course. You will not find the truth anywhere else.”

After using 8chan – an unmoderated board known for its extreme racist, sexist and violent memes – to post his manifesto, Tarrant broadcast the shooting live on Facebook.

A police officer stands guard during Friday prayers at the Baitul Mukarram National Mosque, in Dhaka, Bangladesh, after the Christchurch mosque attacks in New Zealand (Reuters) (REUTERS/Mohammad Ponir Hossain)

The camera angle used appeared to emulate popular first-person-shooter video games, and he shouted the internet meme “subscribe to PewDiePie” before the massacre was launched.

The phrase, which grew out of a battle to keep PewDiePie as the most-subscribed YouTube channel, was one of several memes used by Tarrant in his video and manifesto.

Author Jamie Bartlett said the attack was “wrapped up in dark internet culture in every way”.

Robert Evans, of internet research group Bellingcat, cautioned Tarrant’s manifesto may itself be a form of “s**tposting”, where ironic or false content is used to provoke a response.

“The entire manifesto is dotted, liberally, with references to memes and internet in-jokes that only the extremely online would get,” he wrote.

“They are meant to distract attention from his more honest points, and to draw the attention of his real intended audience.”

Mr Evans suggested that the naming of Candace Owens, of US right-wing student group Turning Point, as an inspiration could be misdirection.

Ms Owens has been praised by Mr Trump and was photographed last week with MPs Jacob Rees-Mogg and Steve Baker, while visiting universities with Turning Point’s new UK chapter.

She denied inspiring the Christchurch attack, but critics cited a November 2018 tweet reading: “If France wants to build an army to defend itself against anything, it ought to be the declining birth rate of its people. All signs indicate that it will be a Muslim majority country in just 40 years! Defend your culture first, Emmanuel Macron.”

Amid condemnation from mainstream figures, prominent YouTubers claimed the New Zealand atrocity was being used to attack their platforms – and the darker forums where Tarrant sourced his views continued to defend them.

On Gab, which styles itself as a “free speech social network”, many far-right users were justifying the attack by claiming the suspect was merely “fighting back” and “resisting invasion”.

On 8chan, where one user hailed Tarrant as “the next Breivik”, anonymous users were openly celebrating the massacre.