One Nation’s candidate for Melbourne has a history of promoting far-right rhetoric about waging religious war against Muslims, using misogynistic language and spreading COVID-19 conspiracy theories.

Matthew Collins has deleted or locked his social media accounts since being selected as a candidate – one of 112 running for Pauline Hanson’s party at next month’s state election.

But The Age has obtained a catalogue of his X (Twitter) posts captured before he shut down his account, and has verified them using data-scraping tools which archived some of his almost 17,000 posts made over the previous decade.

His posts display a fixation with a perceived clash of civilisations between Christians and Muslims, which an extremism researcher said was a preoccupation of extreme right-wing figures that should be rejected.

One Nation refused to answer detailed questions about Collins’ posts, including his calls to “decolonise” parts of the Muslim world and his frequent references to the Christian crusades. The candidate did not respond to attempts to contact him through his election campaign Facebook page this week.

The party’s candidate profile for Collins says the 35-year-old works in sales and is running in the Greens-held seat to restore community safety and government responsibility, and to ease cost-of-living pressures.

One Nation is currently polling at a 23 per cent primary vote, according to the latest Resolve Political Monitor conducted for this masthead, suggesting the party will for the first time have a significant presence in the next Victorian parliament.

Collins, whose profile picture on X portrays himself as a knight, posted in November last year: “If you thought the crusades ended with Richard the Lionheart, you’ve got another thing coming.”

In another post, he suggests that The World Decolonization Forum – an academic event that examines the legacy of colonisation – should “decolonise constantiople [sic]… and syria and kurdistan”.

Another post in August features a picture of the Battle of Clavijo in 884AD captioned “RECONQUISTA” – a reference to the Christian military campaigns to retake what is now Spain and Portugal from Muslim rule.

Expelling Muslims from the Turkish capital Istanbul – previously called Constantinople when it was the capital of the Christian Byzantine Empire – is a tenet of some extreme far-right ideologies.

Brenton Tarrant, the Australian man who murdered 51 Muslims in the 2019 Christchurch shootings, referred in his manifesto to “coming for Constantinople” and making it “Christian owned once more”. Tarrant also inscribed “Clavijo 844” on his weapon before opening fire.

Anders Breivik, who killed 77 people in a terrorist attack in Norway in 2011 and inspired Tarrant, referred to the “Reconquista” several times in his manifesto and also adopted crusader iconography.

There is no suggestion Collins endorses violent extremism, only that his online posts closely align with elements of some of those ideologies.

Deakin University political extremism researcher Josh Roose said Collins was using the language of elements of the extreme right which was preoccupied with the idea of launching a modern Crusade against Muslims.

“It’s the idea of the need for a modern great crusade to take on global Islam aggressively, to fight it. He’s talking about decolonising Constantinople, which means effectively to rid it entirely of its Muslim population,” Roose said.

“You can only imagine how that would be read by Muslim communities in Australia but more broadly the wider Australian community.

“It actually speaks to the violent rhetoric that underpins a lot of the extreme right. If One Nation wants any claim to be developing into and becoming a mass political party, they would do well to reject rhetoric of religious conquest and exclusion associated with elements of the extreme right.”

In other X posts, Collins sent images of the September 11 terrorist attacks to New York mayor Zohran Mamdani, and referred to Mamdani, who is Muslim, as having a “jihad face”.

In one post Collins also uses the term “foid”, a term taken from the misogynistic “manosphere” subculture. A glossary compiled by the United Nation defines “foid” as a dehumanising word for women meaning “female humanoid organism”.

Collins’ selection as a One Nation candidate has exercised support for the party from members of banned neo-Nazi group, the National Socialist Network, with prominent member Michael Nelson – who attended One Nation’s campaign launch earlier this month – describing Collins on X as a “patriot”.

However, Collins has previously argued against the NSN’s brand of white ethnonationalism, and suggested the group is a “psyop” (psychological operation) created by the Australian Federal Police.

In other posts, he theorised that ASIO’s concern about violent right-wing extremism was a ploy to deliberately provoke a far-right terrorist attack – a “brenton tarrant type lunatic to take extreme overreaction” – to give the federal government a pretext to curtail Australians’ freedoms.

Collins also posted a theory earlier this year that COVID-19 was “released on purpose” to unseat US President Donald Trump. One Nation Victoria’s leader, Warren Pickering, has also publicly endorsed the “great reset” conspiracy theory which states the pandemic was deliberately facilitated.

Hanson has frequently attacked Muslims, including suggesting in March there was no such thing as a “good” Muslim, a comment she has since tried to walk back.

The party’s Victorian campaign launch last Saturday opened with an AI-produced video featuring a Middle Eastern man wearing a bomb vest and a young African man with a machete.

Asked about the video on ABC radio on Monday, deputy state leader Colleen Harkin said she was “not accepting that it’s racist. It’s a messaging issued out to people... about all the things that are going wrong in Australia”.

With Sherryn Groch

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Patrick Hatch is state politics reporter at The Age. Contact him at patrick.hatch@theage.com.au, or via Signal at @pwhatch.61Connect via X or email.