What Tuesday's rally in Tampa made apparent is that devotees of these falsehoods - some of which are specific to faith in the President, others garden-variety nonsense with racist and anti-Semitic undertones - don't just exist on digital message boards. Believers in "QAnon", as the conspiracy theory is known, were front and centre at the Florida State Fairgrounds Expo Hall, where Trump came to stump for Republican candidates. As Trump spoke, a sign rose from the audience. "We are Q", it read. Another poster displayed text arranged in a "Q" pattern: "Where we go one we go all." US President Donald Trump. Credit:AP The symbol appeared on clothing, too. A man and a woman wore matching white T-shirts with the YouTube logo encircled in a blue Q. The video-sharing website came under criticism this week for unwittingly becoming a platform for baseless claims, first promoted on Twitter and Reddit by QAnon believers, that certain Hollywood celebrities are paedophiles.

A search for one of those celebrities' names on Monday returned videos purporting to show his victims sharing their stories. QAnon followers at Donald Trump's Tampa rally on Tuesday. Credit:AP The prominence of the Q symbol turned parts of the audience into a tableau of delusion and paranoia - and offered stark evidence that QAnon, an outgrowth of the #Pizzagate conspiracy theory that led a gunman to open fire in a restaurant last year, has leapt from internet message boards to the President's "Make America Great Again" tour through America. "Pray Trump mentions Q," one user wrote on 8chan. He didn't need to. As hazy corners of the internet buzzed with talk of the President, his appearance became a real-life show of force for the community that has mostly operated behind the veil of anonymity on Reddit. Trump himself has at times been a purveyor of conspiracy theories, most notably in refusing for years to back down from his lie that Barack Obama was not born in the US. He also claimed without evidence that Obama had wiretapped Trump Tower, peddled the debunked idea that millions of illegal votes cost him the popular vote and associated the father of Republican senator Ted Cruz with the assassin who shot John F. Kennedy.

But viewing their message boards, it's clear that QAnon crosses a new frontier. In the black hole of conspiracy, Q followers believe Trump only feigned collusion with Russia to create a pretence for the hiring of Special Counsel Robert Mueller, who, they say, is actually working to expose the Democrats. Barack Obama, Hillary Clinton and George Soros are planning a coup - and traffic children in their spare time. JP Morgan, the American financier, sank the Titanic. Ankle bracelet? US Senator John McCain is also target of conspiracy theories. Credit:Alex Ellinghausen In the world in which QAnon believers live, Trump's detractors, such as Republican senator John McCain and Hillary Clinton aide Huma Abedin, wear ankle monitors that track their whereabouts. Press reports are dismissed as "Operation Mockingbird", the name given to the alleged mid-century infiltration of the American media by the CIA. The Illuminati loom large in QAnon, as do the Rothschilds, a wealthy Jewish family vilified by the conspiracy theorists as leaders of a satanic cult. Among the world leaders wise to satanic influences, the theory holds, is Russian President Vladimir Putin.

QAnon flirts with eschatology, fascist philosophy and the filmmaking of Francis Ford Coppola. Adherents believe a "Great Awakening" will precede the final storm foretold by Trump. Once they make sense of the information dripped by Q, they will usher in a Christian revival presaging total victory. The implication is that resolving the clues would not just explain Trump's planned counter-coup. It would explain the whole universe. When Q is absent for long stretches of time, followers take note. "Please tell me where to go," one wrote last month. "I feel lost without Q." Some big names have bought into the fantasy.

Roseanne Barr, the disgraced star of the cancelled ABC revival that bore her name, has posted messages on Twitter that appear to endorse the QAnon worldview, fixating on child sex abuse. She has sought to make contact with Q on social media and has retweeted messages summarising the philosophy built around the online persona. QAnon has enjoyed promoters ranging from Curt Schilling, the former Boston Red Sox pitcher, to Cheryl Sullenger, the anti-abortion activist. There is a component of QAnon that can be interpreted as a direct call to action, which has already had real-life consequences. The Newport Beach Police Department said recently it was looking into the presence of a man outside Michael Avenatti's law office after a link to the lawyer's website and images of his office building appeared in QAnon threads. This spring, armed members of Veterans on Patrol stumbled on a homeless camp and demanded that authorities investigate it as a site of child sex-trafficking, later thanking QAnon followers for taking up their cause. Washington Post