Christopher Wylie, the whistleblower who exposed the widespread misuse of data by his former employer, Cambridge Analytica, has revealed how the company “weaponised” the fashion industry in the run up to the 2016 US election, which he claims helped Donald Trump get elected.

Speaking at the annual BoF Voices festival in Oxfordshire, Wylie revealed for the first time a matrix based on data collected by the firm which he claims can show how users’ preferences for particular brands on social media platforms – Facebook, in particular – were then used to help target these same users with pro-Trump messaging. He compared the misuse of fashion-based data as one of the campaign’s lesser reported “weapons of mass destruction”.

“They [Cambridge Analytica] looked at actual people. How they engaged with certain brands was put into a funnel and helped build the algorithms,” Wylie explained. “When you look at personality traits, music and fashion are the most informative [tools] for predicting someone’s personality.” A user’s predilection for a particular label gives, he said, a very clear indication of what reports often call “populist political signalling”.

Wylie on stage. Photograph: John Phillips/Getty

Cambridge Analytica, which was shut down earlier this year following an investigation by the Observer, was the political marketing firm headed by Trump’s former key adviser, Steve Bannon, and owned by hedge-fund billionaire Robert Mercer. It also used user information obtained without authorisation in early 2014 – including cultural preferences such as fashion and music – to create a system that could single out voters in order to expose them to specific political advertising.

Prior to the company’s role on Trump’s election campaign, Wylie had been its director of research. Recalling his first meeting with Bannon, he explained how fashion was one of the many things they examined, along with “Judith Butler, Foucault and nature of our fractured self”. He said the pair discussed the difference between Crocs and Chanel’s little black dress as analogous for the fashion spectrum – which would become a blueprint for how the firm used fashion preferences later on.

Wylie went onto to criticise the fashion industry for creating a “pre-existing cultural foundation which allowed the alt-right to grow over that time period”. He conceded that while Cambridge Analytica “exploited the cultural narratives that the fashion and culture industry put out”, the fashion industry was responsible for creating those cultural narratives in the first place. He added: “We need new narratives in culture, and to do a better job of showing more diversity” in order to direct politics along a different route.

According to the data obtained (the majority of which came from US users), certain fans of American denim brands such as Wrangler, Hollister and Lee Jeans could be more closely linked to low levels of openness and mistrust – and therefore more likely to engage with pro-Trump messaging. This data also showed more esoteric fashion labels such as Kenzo or Alexander McQueen tended towards a more open and imaginative fanbase, which Wylie said leant more towards typical democratic voters.

‘When we think about fascist movements, the first thing they do is develop an aesthetic ... ’ Peter Cvjetanovic (right) at the Unite the Right rally in Charlottesville Photograph: Anadolu Agency/Getty Images

Wylie went on to explain that this data was particularly used to target the alt-right: “When we think about fascist movements, the first thing they do is develop an aesthetic,” he said, illustrating his point with the uniforms of the Nazi party and, more recently, alt-right supremacists who, in August 2017 marched through Charlottesville in a uniform of chinos and white polo shirts.

The link between fashion and psychology is nothing new, but this is the first time that it has been exploited in order to influence political thinking, says Wylie. “We [Bannon and I, during that time] said, if we indulge in light stereotyping, [if we look] at culture as a distribution of attributions that plays out in the wider world, we can work out where it goes … ” Fashion is part of the so-called culture wars. “The thing with Crocs and the Chanel dress, one is quick, fast and regrettable, the other is enduring and iconic … it is up to you if Trump or Brexit [are] the Crocs or the Chanel of our political age.”